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Dysregulation of Wnt/β-catenin signaling is frequently observed in human gastric cancer. Elucidation of the tumor immune microenvironment is essential for understanding tumorigenesis and for the development of immunotherapeutic strategies. However, it remains unclear how β-catenin signaling regulates the tumor immune microenvironment in the stomach. Here, we identify CCL28 as a direct transcriptional target gene of β-catenin/T-cell factor (TCF). Protein levels of β-catenin and CCL28 positively correlated in human gastric adenocarcinoma. β-Catenin–activated CCL28 recruited regulatory T (Treg) cells in a transwell migration assay. In a clinically relevant mouse gastric cancer model established by Helicobacter (H.) felis infection and N-methyl-N-nitrosourea (MNU) treatment, inhibition of β-catenin/TCF activity by a pharmacologic inhibitor iCRT14 suppressed CCL28 expression and Treg cell infiltration in the stomach. Moreover, an anti-CCL28 antibody attenuated Treg cell infiltration and tumor progression in H. felis/MNU mouse models. Diphtheria toxin–induced Treg cell ablation restrained gastric cancer progression in H. felis/MNU-treated DEREG (Foxp3-DTR) mice, clarifying the tumor-promoting role of Treg cells. Thus, the β-catenin–CCL28–Treg cell axis may serve as an important mechanism for immunosuppression of the stomach tumor microenvironment. Our findings reveal an immunoregulatory role of β-catenin signaling in stomach tumors and highlight the therapeutic potential of CCL28 blockade for the treatment of gastric cancer. Significance: These findings demonstrate an immunosuppressive role of tumor-intrinsic β-catenin signaling and the therapeutic potential of CCL28 blockade in gastric cancer.

Metabolic status is essential in maintaining normal functions of hematopoietic stem cells (HSCs). However, how the dynamic of the mitochondrion, as a central organelle in metabolism, is molecularly regulated to orchestrate metabolism and HSC stemness remains to be elucidated. Here, we focus on the role of Zeb1, a well-characterized epithelial-to-mesenchymal transition (EMT) inducer which has been demonstrated to confer stem-cell-like characteristics in multiple cancer types in stemness regulation of HSCs. Using a Zeb1-tdTomato reporter mouse model, we find that Zeb1+Lin−Sca-1+c-Kit+ cells (Zeb1+-LSKs) represent a subset of functional long-term HSCs. Zeb1+LSKs exhibit a reduced reactive oxygen species (ROS) level, low mitochondrial mass, low mitochondrial membrane potential (MMP), and particularly small, round fragmented mitochondria. Of note, ectopic expression of Zeb1 leads to a fragmented mitochondrial morphology with a low mitochondrial metabolic status in EML cells. In addition, Zeb1-knockout (Zeb1-KO) LSKs from fetal liver display an exhausted stem-cell activity. Zeb1 deficiency results in elongated and tubulated mitochondria with increased mitochondrial mass, elevated MMP, and higher ROS production. Mechanistically, Zeb1 acts as a transcriptional suppressor on the key mitochondrial-fusion protein Mitofusin-2 (encoded by Mfn2). We highlight an important role of Zeb1 in the regulation of mitochondrial morphology in HSC and the metabolic control of HSC stemness by repressing Mfn2-mediated mitochondrial fusion.

Objectives In contrast to extensive studies on bone metastasis in advanced prostate cancer (PCa), liver metastasis has been under‐researched so far. In order to decipher molecular and cellular mechanisms underpinning liver metastasis of advanced PCa, we develop a rapid and immune sufficient mouse model for liver metastasis of PCa via orthotopic injection of organoids from PbCre+; rb1f/f;p53f/f mice. Materials and Methods PbCre+;rb1f/f;p53f/f and PbCre+;ptenf/f;p53f/f mice were used to generate PCa organoid cultures in vitro. Immune sufficient liver metastasis models were established via orthotopic transplantation of organoids into the prostate of C57BL/6 mice. Immunofluorescent and immunohistochemical staining were performed to characterize the lineage profile in primary tumour and organoid‐derived tumour (ODT). The growth of niche‐labelling reporter infected ODT can be visualized by bioluminescent imaging system. Immune cells that communicated with tumour cells in the liver metastatic niche were determined by flow cytometry. Results A PCa liver metastasis model with full penetrance is established in immune‐intact mouse. This model reconstitutes the histological and lineage features of original tumours and reveals dynamic tumour‐immune cell communication in liver metastatic foci. Our results suggest that a lack of CD8+ T cell and an enrichment of CD163+ M2‐like macrophage as well as PD1+CD4+ T cell contribute to an immuno‐suppressive microenvironment of PCa liver metastasis. Conclusions Our model can be served as a reliable tool for analysis of the molecular pathogenesis and tumour‐immune cell crosstalk in liver metastasis of PCa, and might be used as a valuable in vivo model for therapy development., Liu et al. developed a rapid and immune sufficient mouse model for liver metastasis of prostate cancer via orthotopic injection of organoid cultures from PbCre+; rb1f/f;p53f/f mice. Using a niche‐labeling lentiviral reporter, a dynamic tumor‐immune cell communication at different phases in the liver metastatic niche is depicted. A paucity of CD8+ T cells and abundant PD1+ CD4+ T cells and CD163+ M2 macrophages contribute to an immune suppressive liver metastatic niche. ​

The basal cell compartment in many epithelial tissues is generally believed to serve as an important pool of stem cells. However, basal cells are heterogenous and the stem cell subpopulation within basal cells is not well elucidated. Here we uncover that the core epithelial-to-mesenchymal transition (EMT) inducer Zeb1 is expressed in a prostate basal cell subpopulation. The Zeb1+ prostate epithelial cells are multipotent prostate basal stem cells (PBSCs) that can self-renew and generate functional prostatic glandular structures at the single-cell level. Genetic ablation studies reveal an indispensable role for Zeb1 in prostate basal cell development. Utilizing unbiased single-cell transcriptomic analysis of over 9000 mouse prostate basal cells, we confirm the existence of the Zeb1+ basal cell subset. Moreover, Zeb1+ epithelial cells can be detected in mouse and human prostate tumors. Identification of the PBSC and its transcriptome profile is crucial to advance our understanding of prostate development and tumorigenesis., Heterogeneous populations of basal cells in the prostate epithelium contain stem cells. Here the authors show that Zeb1 marks a pool of prostate epithelial stem cells that self-renew, generate prostate glandular structures with all 3 epithelial cell types and are required for prostate basal cell development.

Summary Although STAT3 signaling is demonstrated to regulate sensory cell differentiation and regeneration in the zebrafish, its exact role is still unclear in mammalian cochleae. Here, we report that STAT3 and its activated form are specifically expressed in hair cells during mouse cochlear development. Importantly, conditional cochlear deletion of Stat3 leads to an inhibition on hair cell differentiation in mice in vivo and in vitro. By cell fate analysis, inactivation of STAT3 signaling shifts the cell division modes from asymmetric to symmetric divisions from supporting cells. Moreover, inhibition of Notch signaling stimulates STAT3 phosphorylation, and inactivation of STAT3 signaling attenuates production of supernumerary hair cells induced by a Notch pathway inhibitor. Our findings highlight an important role of the STAT3 signaling during mouse cochlear hair cell differentiation and may have clinical implications for the recovery of hair cell loss-induced hearing impairment., Highlights • STAT3 signaling is activated during hair cell development and regeneration • Inactivation of STAT3 signaling inhibits hair cell differentiation in vivo and in vitro • STAT3 signaling regulates symmetric and asymmetric cell division modes • STAT3 partially mediates Notch signaling-controlled hair cell production, The mechanism of mammalian hair cell development is not fully understood. In this article, Wei-Qiang Gao and colleagues show that inactivation of STAT3 signaling impairs mammalian cochlear hair cell differentiation, by influencing asymmetric and symmetric cell division modes. The STAT3 pathway is downstream of the Notch signaling for the regulation of hair cell production.

Tumor metastasis is the major cause of death for prostate cancer (PCa) patients. However, the treatment options for metastatic PCa are very limited. Epithelial-mesenchymal transition (EMT) has been reported to be an indispensable step for tumor metastasis and is suggested to associate with acquisition of cancer stem cell (CSC) attributes. We propose that small-molecule compounds that can reverse EMT or induce mesenchymal-epithelial transition (MET) of PCa cells may serve as drug candidates for anti-metastasis therapy. Methods: The promoters of CDH1 and VIM genes were sub-cloned to drive the expression of firefly and renilla luciferase reporter in a lentiviral vector. Mesenchymal-like PCa cells were infected with the luciferase reporter lentivirus and subjected to drug screening from a 1274 approved small-molecule drug library for the identification of agents to reverse EMT. The dosage-dependent effect of candidate compounds was confirmed by luciferase reporter assay and immunoblotting. Wound-healing assay, sphere formation, transwell migration assay, and in vivo intracardiac and orthotopic tumor xenograft experiments were used to evaluate the mobility, metastasis and tumor initiating capacity of PCa cells upon treatment. Possible downstream signaling pathways affected by the candidate compound treatment were analyzed by RNA sequencing and immunoblotting. Results: Drug screening identified Amlexanox, a drug used for recurrent aphthous ulcers, as a strong agent to reverse EMT. Amlexanox induced significant suppression of cell mobility, invasion, serial sphere formation and in vivo metastasis and tumor initiating capacity of PCa cells. Amlexanox treatment led to downregulation of the IKK-ɛ/ TBK1/ NF-κB signaling pathway. The effect of Amlexanox on EMT reversion and cell mobility inhibition can be mimicked by other IKK-ɛ/TBK1 inhibitors and rescued by reconstitution of dominant active NF-κB. Conclusions: Amlexanox can sufficiently suppress PCa metastasis by reversing EMT through downregulating the IKK-ɛ/TBK1/NF-κB signaling axis.

Background & Aims Little is known about factors that promote gastric carcinogenesis. We analyzed multiple microarray data sets for messenger RNAs (mRNAs) that were increased significantly in human gastric tumor samples, compared with the adjacent normal gastric tissue. We found expression of tripartite motif 59 ( TRIM59 ), which encodes a putative ubiquitin ligase, to be increased, and investigated its effects in gastric cancer cell lines. Methods We analyzed microarray data sets from the Oncomine database. We used quantitative polymerase chain reaction and immunoblotting to measure levels of TRIM59 mRNA and protein in 50 human gastric cancer and paired normal tissues, obtained from Renji Hospital and the First Affiliated Hospital of Nanchang University, in China. We also measured protein levels in the gastric epithelial cell line GES-1; the cancer cell lines MKN45, AGS, SGC7901, BGC823, Snu5, N87, and Snu1; and in tissue arrays of 108 human gastric tumors. TRIM59 was knocked down and overexpressed in gastric cancer cell lines, and the effects on proliferation, clone formation, migration, and growth of xenograft tumors in nude mice were assessed. TRIM59-related signaling pathways were examined by immunoblotting and quantitative polymerase chain reaction. We analyzed interactions among TRIM59, P53, and ubiquitin in immunoprecipitation studies. Results Levels of TRIM59 mRNA and protein were increased significantly in gastric tumors compared with nontumor tissues; increased levels were associated with advanced tumor stage and shorter patient survival times. TRIM59 knockdown reduced proliferation, clone formation, and migration of gastric cancer cell lines, as well as growth of xenograft tumors in nude mice; overexpression of TRIM59 had the opposite effects. TRIM59 interacted physically with P53, increasing its ubiquitination and degradation. Increased levels of TRIM59 in human gastric tumors correlated with reduced expression of P53 target genes. Conclusions The putative ubiquitin ligase TRIM59 is up-regulated in human gastric tumors compared with nontumor tissues. Levels of TRIM59 correlate with tumor progression and patient survival times. TRIM59 interacts with P53, promoting its ubiquitination and degradation, and TRIM59 might promote gastric carcinogenesis via this mechanism.

Cerebellar granule neuronal progenitors (GNPs) are the precursors of cerebellar granule cells (CGCs) and are believed to be the cell of origin for medulloblastoma (MB), yet the molecular mechanisms governing GNP neurogenesis are poorly elucidated. Here, we demonstrate that storkhead box 1 (Stox1), a forkhead transcriptional factor, has a pivotal role in cerebellar granule neurogenesis and MB suppression. Expression of Stox1 is upregulated along with GNP differentiation and repressed by activation of sonic hedgehog (SHH) signaling. Stox1 exerts its neurogenic and oncosuppressing effect via direct transcriptional repression of Math1, a basic helix-loop-helix transcription activator essential for CGC genesis. This study illustrates a SHH-Stox1-Math1 regulatory axis in normal cerebellar development and MB formation.

Cell polarity and correct mitotic spindle positioning are essential for the maintenance of a proper prostate epithelial architecture, and disruption of the two biological features occurs at early stages in prostate tumorigenesis. However, whether and how these two epithelial attributes are connected in vivo is largely unknown. We herein report that conditional genetic deletion of E-cadherin, a key component of adherens junctions, in a mouse model results in loss of prostate luminal cell polarity and randomization of spindle orientations. Critically, E-cadherin ablation causes prostatic hyperplasia which progresses to invasive adenocarcinoma. Mechanistically, E-cadherin and the spindle positioning determinant LGN interacts with the PDZ domain of cell polarity protein SCRIB and form a ternary protein complex to bridge cell polarity and cell division orientation. These findings provide a novel mechanism by which E-cadherin acts an anchor to maintain prostate epithelial integrity and to prevent carcinogenesis in vivo., Author summary Luminal cells are the most abundant type of the prostate epithelial cells. Most prostate cancers also display a luminal phenotype. Horizontal cell division of luminal cells allows the surface expansion of the secretory prostate lumen and meanwhile maintains the monolayer and polarized epithelial architecture. Disruption of the epithelial integrity and appearance of multilayer epithelia are early events in prostate adenocarcinoma development. However, the molecular mechanism that ensures the horizontal division in luminal cells remains largely unknown. Here, we generated a genetically engineered mouse model in which E-cadherin, a key component of the adherens junction that serves to connect the lateral plasma membrane of neighboring epithelial cells, was knocked out in the prostate luminal cells. E-cadherin deletion leads to loss of cell polarity and disoriented cell division, which subsequently causes dysregulated cell proliferation and strongly predisposes mice for prostate tumorigenesis. Importantly, we revealed that E-cadherin acts as an anchor to recruit cell polarity protein SCRIB and spindle positioning determinant LGN to the lateral cell membrane, thereby ensure a proper alignment of the cell division plane. All these findings uncover a novel mechanism by which E-cadherin links cell polarity and spindle orientation to keep prostate epithelial integrity and prevent carcinogenesis.

Previous data suggested a negative role of phosphatase and tensin homolog (Pten) and a positive function of SH2-containing tyrosine phosphatase (Shp2)/Ptpn11 in myelopoiesis and leukemogenesis. Herein we demonstrate that ablating Shp2 indeed suppressed the myeloproliferative effect of Pten loss, indicating directly opposing functions between pathways regulated by these two enzymes. Surprisingly, the Shp2 and Pten double-knockout mice suffered lethal anemia, a phenotype that reveals previously unappreciated cooperative roles of Pten and Shp2 in erythropoiesis. The lethal anemia was caused collectively by skewed progenitor differentiation and shortened erythrocyte lifespan. Consistently, treatment of Pten-deficient mice with a specific Shp2 inhibitor suppressed myeloproliferative neoplasm while causing anemia. These results identify concerted actions of Pten and Shp2 in promoting erythropoiesis, while acting antagonistically in myeloproliferative neoplasm development. This study illustrates cell type-specific signal cross-talk in blood cell lineages, and will guide better design of pharmaceuticals for leukemia and other types of cancer in the era of precision medicine.

// Yun-Li Chang 1 , Pei-Jie Zhou 1 , Lianzi Wei 1 , Wang Li 1 , Zhongzhong Ji 1 , Yu-Xiang Fang 1 , Wei-Qiang Gao 1, 2, 3 1 State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China 2 School of Biomedical Engineering & Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China 3 Collaborative Innovation Center of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200030, China Correspondence to: Wei-Qiang Gao, e-mail: gao.weiqiang@sjtu.edu.cn Yu-Xiang Fang, e-mail: fyx2003108@sina.com Keywords: miR-7, prostate cancer, cancer stem cells, tumorigenesis, KLF4, PI3K/Akt pathway Received: February 28, 2015 Accepted: June 19, 2015 Published: June 29, 2015 ABSTRACT Up to now, the molecular mechanisms underlying the stemness of prostate cancer stem cells (PCSCs) are still poorly understood. In this study, we demonstrated that microRNA-7 (miR-7) appears to be a novel tumor-suppressor miRNA, which abrogates the stemness of PCSCs and inhibits prostate tumorigenesis by suppressing a key stemness factor KLF4. MicroRNA-7 is down-regulated in prostate cancer cells compared to non-tumorigenic prostate epithelial cells. Restoration of miR-7 suppresses the expression of the stemness factor KLF4 in PCSCs and inhibits prostate tumorigenesis both in vitro and in vivo . Interestingly, the suppression of the stemness of PCSCs by miR-7 is sustained for generations in xenografts. Analysis of clinical samples also revealed a negative correlation between miR-7 expression and prostate tumor progression. Mechanistically, overexpression of miR-7 may lead to a cell cycle arrest but not apoptosis, which seems achieved via suppressing the KLF4/PI3K/Akt/p21 pathway. This study identifies miR-7 as a suppressor of PCSCs' stemness and implicates its potential application for PCa therapy.