Farnesoid X receptor mediates macrophage-intrinsic responses to suppress colitis-induced colon cancer progression.

Bile acids (BAs) affect the intestinal environment by ensuring barrier integrity, maintaining microbiota balance, regulating epithelium turnover, and modulating the immune system. As a master regulator of BA homeostasis, farnesoid X receptor (FXR) is severely compromised in patients with inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CAC). At the front line, gut macrophages react to the microbiota and metabolites that breach the epithelium. We aim to study the role of the BA/FXR axis in macrophages. This study demonstrates that inflammation-induced epithelial abnormalities compromised FXR signaling and altered BAs' profile in a mouse CAC model. Further, gut macrophage-intrinsic FXR sensed aberrant BAs, leading to pro-inflammatory cytokines' secretion, which promoted intestinal stem cell proliferation. Mechanistically, activation of FXR ameliorated intestinal inflammation and inhibited colitis-associated tumor growth, by regulating gut macrophages' recruitment, polarization, and crosstalk with Th17 cells. However, deletion of FXR in bone marrow or gut macrophages escalated the intestinal inflammation. In summary, our study reveals a distinctive regulatory role of FXR in gut macrophages, suggesting its potential as a therapeutic target for addressing IBD and CAC.

Regulation of RB1CC1/FIP200 stability and autophagy function by CREBBP-mediated acetylation in an intrinsically disordered region.

RB1CC1/FIP200 is an essential macroautophagy/autophagy protein that plays an important role in a variety of biological and disease processes through its canonical autophagy-dependent and -independent functions. However, it remains largely unknown whether post-translational modifications could regulate RB1CC1 and its associated autophagy functions. Here, we report acetylation of several lysine residues of RB1CC1 by acetyltransferase CREBBP (CREB binding protein), with K276 as the major CREBBP acetylation site. K276 is also identified as a ubiquitination site by mass spectrometry, and acetylation at this site reduces ubiquitination of RB1CC1 to inhibit its ubiquitin-dependent degradation. We also find that RB1CC1 contains an N-terminal intrinsically disordered region (IDR) capable of forming liquid-liquid phase separation (LLPS) in vitro, which may drive formation of RB1CC1 puncta with LLPS properties in cells independent of SQSTM1/p62 and other autophagy receptors CALCOCO2/NDP52, NBR1, TAX1BP1 and OPTN. Mutational analysis shows that both K276 acetylation and the N-terminal IDR containing it are important for maintaining canonical autophagy function of RB1CC1 in breast cancer cells. Our findings demonstrate regulation of RB1CC1 by a new post-translational mechanism and suggest potential therapeutic application of inducing RB1CC1 degradation through blocking K276 acetylation in the treatment of cancer and other diseases.Abbreviations: Baf-A1: bafilomycin A1; CREBBP/CBP: CREB binding protein; CHX: cycloheximide; EP300/p300: E1A binding protein p300; FRAP: fluorescence recovery after photobleaching; HADCs: histone deacetylases; IDR: intrinsically disordered region; LLPS: liquid-liquid phase separation; KAT2A/GCN5: lysine acetyltransferase 2A; KAT2B/PCAF: lysine acetyltransferase 2B; KAT5/TIP60: lysine acetyltransferase 5; KAT8/MOF: lysine acetyltransferase 8; NAM: nicotinamide; PAS: phagophore assembly site; PEG-8000: polyethylene glycol 8000; RB1CC1/FIP200: RB1 inducible coiled-coil 1; TSA: trichostatin A.

Profiling Fusobacterium infection at high taxonomic resolution reveals lineage-specific correlations in colorectal cancer.

The bacterial genus Fusobacterium promotes colorectal cancer (CRC) development, but an understanding of its precise composition at the species level in the human gut and the relevant association with CRC is lacking. Herein, we devise a Fusobacterium rpoB amplicon sequencing (FrpoB-seq) method that enables the differentiation of Fusobacterium species and certain subspecies in the microbiota. By applying this method to clinical tissue and faecal samples from CRC patients, we detect 62 Fusobacterium species, including 45 that were previously undescribed. We additionally reveal that Fusobacterium species may display different lineage-dependent functions in CRC. Specifically, a lineage (designated L1) including F. nucleatum, F. hwasookii, F. periodonticum and their relatives (rather than any particular species alone) is overabundant in tumour samples and faeces from CRC patients, whereas a non-enriched lineage (designated L5) represented by F. varium and F. ulcerans in tumours has a positive association with lymphovascular invasion.

Hepatocyte nuclear factor HNF1A is a potential regulator in shaping the super-enhancer landscape in colorectal cancer liver metastasis.

Super-enhancers (SEs) play essential roles in colorectal cancer (CRC) progression. However, how the SE landscape is orchestrated by transcriptional regulators and evolves is not clear. Using de novo motif analysis, we show that the hepatocyte nuclear factor 1 (HNF1)-binding motif is enriched in SEs in cell lines derived from liver metastases, but not in those from primary tumors. This finding was further validated by extending the method to pancreatic cancer and a pair of isogenic CRC lines. Next, we revealed HNF1-alpha (HNF1A) was majorly expressed and upregulated in CRC liver metastatic cell lines. Clinically, HNF1A was remarkably upregulated in synchronous liver metastases as compared to localized tumors. Collectively, our study implicates HNF1A as a key regulator in shaping the SE landscape in CRC liver metastasis.

Functional cooperation between co-amplified genes promotes aggressive phenotypes of HER2-positive breast cancer.

MED1 (mediator subunit 1) co-amplifies with HER2, but its role in HER2-driven mammary tumorigenesis is still unknown. Here, we generate MED1 mammary-specific overexpression mice and cross them with mouse mammary tumor virus (MMTV)-HER2 mice. We observe significantly promoted onset, growth, metastasis, and multiplicity of HER2 tumors by MED1 overexpression. Further studies reveal critical roles for MED1 in epithelial-mesenchymal transition, cancer stem cell formation, and response to anti-HER2 therapy. Mechanistically, RNA sequencing (RNA-seq) transcriptome analyses and clinical sample correlation studies identify Jab1, a component of the COP9 signalosome complex, as the key direct target gene of MED1 contributing to these processes. Further studies reveal that Jab1 can also reciprocally regulate the stability and transcriptional activity of MED1. Together, our findings support a functional cooperation between these co-amplified genes in HER2+ mammary tumorigenesis and their potential usage as therapeutic targets for the treatment of HER2+ breast cancers.

Integrin α5 subunit is required for the tumor supportive role of fibroblasts in colorectal adenocarcinoma and serves as a potential stroma prognostic marker.

The tumorigenesis of colorectal cancer (CRC) is a complicated process, involving interactions between cancer cells and the microenvironment. The role of α5 integrin subunit in CRC remains controversial, and previous studies mainly focused on cancer cells. Herein, we report an important role of α5 in stroma fibroblasts in the tumorigenesis of CRC. The expression of α5 was found to be located in colorectal tumor stroma rather than in epithelia cancer cells. Immunofluorescence colocalization and gene correlation analysis confirmed that α5 was mainly expressed in cancer-associated fibroblasts (CAFs). Moreover, experimental evidence showed that α5 expression was required for the tumor-promoting effect of fibroblast cells. In an in vivo xenograft nude mice model, α5 depletion in fibroblasts dramatically suppressed fibroblast-induced tumor growth. In an in vitro cell coculture assay, α5 depletion or knockdown reduced the ability of fibroblasts to promote cancer cell migration and invasion compared with wild-type fibroblasts; moreover, we observed that the expression and assembly of fibronectin were downregulated after α5 depletion or knockdown in fibroblasts. Analysis of the RNA-Seq data of the Cancer Genome Atlas cohort revealed that high expression of ITGA5 (α5 integrin subunit) was correlated with poor overall survival in colorectal adenocarcinoma, which was further confirmed by immunohistochemistry in an independent cohort of 355 patients. Thus, our study identifies α5 integrin subunit as a novel stroma molecular marker for colorectal adenocarcinoma, offers a fresh insight into colorectal adenocarcinoma progression, and shows that α5 expression in stroma fibroblasts underlies its ability to promote the tumorigenesis of colorectal adenocarcinoma.

Protocadherin γ-A7 is down-regulated in colorectal cancer and associated with the prognosis in patients with wild-type KRAS.

Many clustered protocadherin genes (PCDHs) within chromosome 5q31 are frequently down-regulated in colorectal cancer (CRC) due to the hypermethylation of this region, and some of them have been identified as tumor suppressors. However, the association between the expression of the clustered PCDHs and prognosis of CRC patients is still unclear. Here, we identified multiple PCDHs that were significantly down-regulated in CRC by analyzing the RNA-seq data of the Cancer Genome Atlas (TCGA) cohort. Among them, one γ-PCDH subfamily member, PCDHGA7, was found to be associated with overall survival in the patients with wild-type KRAS. Next, we experimentally validated the decrease of PCDHGA7 mRNA and protein levels in tumor tissues of 20 CRC patients by using quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry assay (IHC). To further investigate whether the expression of PCDHGA7 could predict clinical outcomes, an independent cohort of 138 patients, whose tumors carried wild-type KRAS, was enrolled. In-house tissue microarrays (TMAs) were developed to facilitate the protein detection, and prognostic significance was analyzed. The result showed low PCDHGA7 expression was associated with advanced TNM stage, high risk of tumor recurrence and short overall survival. In conclusion, this study demonstrates that PCDHGA7 is down-regulated in CRC, and its expression level is correlated with clinical outcomes in patients with wild-type KRAS. Our finding indicates PCDHGA7 could serve as a potential novel biomarker to predict prognosis by combining certain tumor genotypes in patients of CRC.

Stomach wall structure and vessels imaging by acoustic resolution photoacoustic microscopy.

AIM: To image stomach wall blood vessels and tissue, layer-by-layer. METHODS: We built up the acoustic resolution photoacoustic microscopy (AR-PAM) system for imaging layered tissues, such as the stomach wall. A tunable dye laser system was coupled to a fiber bundle. The fibers of the bundle were placed in nine directions with an incident angle of 45° around a high-frequency ultrasound transducer attached to the acoustic lens. This structure formed a dark field on the tissue surface under the acoustic lens and the nine light beams from the fibers to be combined near the focal point of the acoustic lens. The sample piece was cut from a part of the porcine stomach into a petri dish. In order to realize photoacoustic depth imaging of tumor, we designed a tumor model based on indocyanine green (ICG) dye. The ICG solution (concentration of 129 µM/mL) was mixed into molten gel, and then a gel mixture of ICG (concentration of 12.9 µM/mL) was injected into the stomach submucosa. The injection quantity was controlled by 0.1 mL to make a small tumor model. RESULTS: An acoustic resolution photoacoustic microscopy based on fiber illumination was established and an axial resolution of 25 µm and a lateral resolution of 50 µm in its focal zone range of 500 µm has been accomplished. We tuned the laser wavelength to 600 nm. The photoacoustic probe was driven to do B-scan imaging in tissue thickness of 200 µm. The photoacoustic micro-image of mucosa and submucosa of the tissue have been obtained and compared with a pathological photograph of the tissue stained by hematoxylin-eosin staining. We have observed more detailed internal structure of the tissue. We also utilized this photoacoustic microscopy to image blood vessels inside the submucosa. High contrast imaging of the submucosa tumor model was obtained using ICG dye. CONCLUSION: This AR-PAM is able to image layer-by-layer construction and some blood vessels under mucosa in the stomach wall without any contrast agents.

Anoctamin5 regulates cell migration and invasion in thyroid cancer.

Anoctamin/TMEM16 family members have recently been identified as novel calcium-activated chloride channels, and dysregulation of many family members participates in tumorigenesis and progression. However, the exact role of anoctamin5 (ANO5), one member of this family, in thyroid cancer is still not clarified. In this study, we firstly found that the expression levels of ANO5 was significantly downregulated in thyroid cancer compared to adjacent normal tissue by mining the public GEO database. Subsequently, we further demonstrated that the expression levels of ANO5 was significantly downregulated in 69.5% (57/82) clinical thyroid cancer tissues using real-time PCR assay. Moreover, western blot assay also showed that ANO5 was downregulated in papillary thyroid cancer and follicular thyroid cancer compared to adjacent noncancerous tissues. Furthermore, some biological and functional in vitro experiments proved that ANO5 knockdown promotes thyroid cancer cell migration and invasion but overexpression of ANO5 inhibits these phenotypes. By analyzing gene set enrichment, we found that lower ANO5 expression was positively associated with JAK/STAT3 signaling pathway. Collectively downregulation of ANO5 promotes thyroid cancer cell migration and invasion by affecting JAK/STAT3 pathway.

Targeting endogenous DLK1 exerts antitumor effect on hepatocellular carcinoma through initiating cell differentiation.

Cancer stem cells (CSCs) are responsible for tumor initiation and progression. We previously showed that Delta-like homolog 1 (DLK1) may be a therapeutic target against the CSCs of human hepatocellular carcinoma (HCC). However, the therapeutic efficacy and underlying mechanism remain unclear. Here we demonstrated that knockdown of DLK1 using a tet-inducible short hairpin RNA (shRNA) system significantly inhibited proliferation, spheroid formation and in vivo xenograft tumor growth of human HCC cells. Furthermore, in an orthotopic xenograft mouse model, adenovirus-mediated DLK1 knockdown could significantly reduce tumor size, as shown by in vivo imaging approach. Subsequently, an adenoviral vector harboring mouse Dlk1 shRNA was applied. The results showed that Dlk1 knockdown also could inhibit tumor progression in a diethylnitrosamine (DEN) induced mouse HCC model. At cellular mechanism, DLK1 knockdown delayed the cell cycle G1-S transition, along with the decreased expression of cyclin E1 and D1. Significantly, DLK1 knockdown resulted in the decrease of molecular markers such as AFP and EpCAM for hepatic progenitor cells, but the increase of KRT18 and KRT19 for the differentiated hepatocytes. The collective data indicated that targeting endogenous DLK1 may exert antitumor effect on HCCs possibly through initiating cell differentiation.

Epigenetic silencing of JMJD5 promotes the proliferation of hepatocellular carcinoma cells by down-regulating the transcription of CDKN1A 686.

Proteins that contain jumonji C (JmjC) domains have recently been identified as major contributors to various malignant human cancers through epigenetic remodeling. However, the roles of these family members in the pathogenesis of hepatocellular carcinoma (HCC) are obscure. By mining public databases, we found that the HCC patients with lower JmjC domain-containing protein 5 (JMJD5) expression exhibited shorter survival time. We then confirmed that JMJD5 expression was indeed decreased in HCC specimens, which was caused by the altered epigenetic histone modifications, the decreased H3K9ac, H3K27ac and H3K4me2/3 together with the increased trimethylation of H3K27 and H3K9 on the JMJD5 promoter. Functional experiments revealed that JMJD5 knockdown promoted HCC cell proliferation and in vivo tumorigenicity by accelerating the G1/S transition of the cell cycle; in contrast, ectopic JMJD5 expression had the opposite effects. At molecular mechanism, we found that, in HCC cell lines including TP53-null Hep3B, JMJD5 knockdown led to the down-regulation of CDKN1A and ectopic expression of JMJD5 not only increased but also rescued CDKN1A transcription. Moreover, CDKN1A knockdown could abrogate the effect of JMJD5 knockdown or overexpression on cell proliferation, suggesting that JMJD5 inhibits HCC cell proliferation mainly by activating CDKN1A expression. We further revealed that JMJD5 directly enhances CDKN1A transcription by binding to CDKN1A's promoter independent of H3K36me2 demethylase activity. In short, we first prove that JMJD5 is a tumor suppressor gene in HCC pathogenesis, and the epigenetic silencing of JMJD5 promotes HCC cell proliferation by directly down-regulating CDKN1A transcription.

[Supply-demand level and development capability of Harbin urban ecosystem].

To measure the supply-demand level and the development capability of urban ecolsystem is the prerequisite in ensuring urban sustainable development. By using the analysis model of ecological footprint and the improved model of urban ecological carrying capacity, the utilization rate and supply degree of natural resources in Harbin City in 1998-2005 were quantitatively studied, with the supply-demand level and development capability of the City's ecosystem measured and analyzed comprehensively. The results showed that in 1998-2005, the demand of Harbin urban ecosystem was greater than its supply. Though the ecological deficit had an annual decrement of 2.45%, the contradiction between demand and supply of the ecosystem was still obvious. The diversity index of ecological footprint and the development capability both presented an overall uptrend, but the increment of the latter was far greater than that of the former, which illustrated the enhancement of the development capability being based on the consumption of ecological resources, and the urban development being of not sustainable. Social economic measures should be adopted to coordinate the contradiction between demand and supply and to realize the sustainable development of Harbin City.