The role of bile acid in intestinal metaplasia.

A precancerous lesion of gastric cancer (GC), intestinal metaplasia (IM) is a pathological transformation of non-intestinal epithelium into an intestinal-like mucosa. It greatly raises the risk of developing the intestinal type of GC, which is frequently observed in the stomach and esophagus. It is understood that esophageal adenocarcinoma's precursor lesion, chronic gastroesophageal reflux disease (GERD), is what causes Barrett's esophagus (BE), an acquired condition. Recently, Bile acids (BAs), which are one of the compositions of gastric and duodenal contents, have been confirmed that it led to the occurrence and development of BE and gastric intestinal metaplasia (GIM). The objective of the current review is to discuss the mechanism of IM induced by bile acids. This review serves as a foundation for further research aimed at improving the way BE and GIM are currently managed.

Trajectories of serum α-fetoprotein and intermediate-stage hepatocellular carcinoma outcomes after transarterial chemoembolization: A longitudinal, retrospective, multicentre, cohort study.

Background: α-fetoprotein (AFP) response has been proven a key tumor marker for hepatocellular carcinoma (HCC), but its definition remains controversial. This study aims to characterize AFP trajectories after transarterial chemoembolization (TACE) and examine its impact on clinical outcomes. Methods: This longitudinal, multicenter, retrospective, cohort study examined data from the electronic medical record system of four hospitals in China between January 1, 2007 to December 31, 2016. A latent class growth mixed model was applied to distinguish potential AFP dynamic changing trajectories. The multivariable Cox models were used to calculate adjusted hazard ratios (aHRs) and 95% CIs for overall survival. Inverse-probability-of-treatment weighted analyses were performed to eliminate unmeasured confounders through marginal structural models. Findings: A total of 881 patients, who had intermediate-stage HCC with AFP repeatedly measured 3 to 10 times, were included in the study. Three distinct trajectories were identified using the latent class growth mixture model: high-rising (25.7%; n = 226), low-stable (58.7%; n = 517), and sharp-falling (AFP serological response, 15.6%; n = 138). Compared with the low-stable class, the aHRs for death were 5.13 (3.71, 7.10) and 0.52 (0.33, 0.81) for the high-rising and sharp-falling class, adjusted by gender, baseline major tumor size, intrahepatic lesions number, and logAFP(smooth). Furthermore, high-rising class had a significantly higher HR in the subgroup of female patients (10.60, 95%CI: 6.29, 17.86), age<55 (6.78, 95%CI: 4.79, 9.59) and Child-Pugh class B (23.01, 95%CI:8.07, 65.63) (P = 0.014, 0.046 and 0.033 for interaction, respectively). Trajectories of AFP had the highest relative importance of each parameter to survival, including largest tumor size, intrahepatic lesions number, Child-Pugh class, and baseline AFP. Interpretation: AFP trajectories were associated with overall survival for intermediate-stage HCC after TACE. Funding: The Natural Science Foundation of Fujian Province (Nos. 2018J01352, 2016J01576 and 2016J01586); the Science and Technology Innovation Joint Foundation of Fujian Province (Nos. 2017Y9125).

Leukemia inhibitory factor inhibits the proliferation of gastric cancer by inducing G1-phase arrest.

Leukemia inhibitory factor (LIF), a member of the interleukin-6 cytokine family, plays a complex role in cancer. LIF inhibits the proliferation and survival of several myeloid leukemia cells but promotes tumor progression and metastasis in many solid tumors. However, the relationship between LIF and gastric cancer has not been well understood. LIF was downregulated in gastric cancer as detected by western blot analysis and immunohistochemistry (IHC). Notably, LIF was downregulated in approximately 70% (56/80) of primary gastric cancers, in which it was significantly associated with advanced clinical stage, lymph node metastasis, and poor overall survival (median 5-year survival = 26 vs. 43 months for patients with high LIF expression and low LIF expression gastric cancer, respectively). To study the potential function of LIF in the downregulation of gastric cancer, we monitored the behavior using proliferation, cell cycle, and flow cytometry analysis. Overexpression of LIF inhibited the gastric cancer cell cycle in the G1 phase. In our experiment, overexpression of LIF by lentivirus upregulated P21 and downregulated cyclin D1. Recombinant human LIF also downregulated P21 and cyclin D1 at various times. A further in vivo tumor formation study in nude mice indicated that overexpression of LIF in gastric cancer significantly delayed the progress of tumor formation. These findings indicate that LIF may serve as a negative regulator of gastric cancer.

Correction: NLRP6 targeting suppresses gastric tumorigenesis via P14ARF-Mdm2-P53-dependent cellular senescence.

[This corrects the article DOI: 10.18632/oncotarget.22876.].

Geminin facilitates FoxO3 deacetylation to promote breast cancer cell metastasis.

Geminin expression is essential for embryonic development and the maintenance of chromosomal integrity. In spite of this protective role, geminin is also frequently overexpressed in human cancers and the molecular mechanisms underlying its role in tumor progression remain unclear. The histone deacetylase HDAC3 modulates transcription factors to activate or suppress transcription. Little is known about how HDAC3 specifies substrates for modulation among highly homologous transcription factor family members. Here, we have demonstrated that geminin selectively couples the transcription factor forkhead box O3 (FoxO3) to HDAC3, thereby specifically facilitating FoxO3 deacetylation. We determined that geminin-associated HDAC3 deacetylates FoxO3 to block its transcriptional activity, leading to downregulation of the downstream FoxO3 target Dicer, an RNase that suppresses metastasis. Breast cancer cells depleted of geminin or HDAC3 exhibited poor metastatic potential that was attributed to reduced suppression of the FoxO3-Dicer axis. Moreover, elevated levels of geminin, HDAC3, or both together with decreased FoxO3 acetylation and reduced Dicer expression were detected in aggressive human breast cancer specimens. These results underscore a prominent role for geminin in promoting breast cancer metastasis via the enzyme-substrate-coupling mechanism in HDAC3-FoxO3 complex formation.

LRP6 targeting suppresses gastric tumorigenesis via P14ARF-Mdm2-P53-dependent cellular senescence.

NLRP6, a member of the Nod-like receptor family, protects against chemically induced intestinal injury and colitis-associated colon cancer. However, the cellular mechanisms involved in this NLRP6-mediated protection remain unclear. Here, we show that NLRP6 was down-regulated in approximately 75% of primary gastric cancer cases and exhibited significant associations with advanced clinical-stage lymph node metastasis and poor overall survival. Functional studies established that ectopic overexpression or down-regulation of NLRP6 inhibited cancer cell proliferation by inducing cell cycle arrest at the G1 phase via P21 and Cyclin D1 both in vitro and in vivo. Activation of the P14ARF-P53 pathway played a crucial role in the observed cellular senescence. We further demonstrated that ectopic overexpression of NLRP6 combined with inactivation of NF-κB(p65) and Mdm2 activates P14ARF-P53 to promote the senescence of gastric cancer cells. These findings indicate that NLRP6 functions as a negative regulator of gastric cancer and offer a potential new option for preventing gastric cancer.

MT3-MMP down-regulation promotes tumorigenesis and correlates to poor prognosis in esophageal squamous cell carcinoma.

The membrane-type matrix metalloproteinases (MT-MMPs) play an important role in degrading the extracellular matrix (ECM) and facilitating protease-dependent tumor progression and invasion. Here, we report that unlike MT1-MMP, MT3-MMP was down-regulated in esophageal squamous cell carcinoma (ESCC) as detected by real-time PCR (qPCR), Western blot analysis, and immunohistochemistry (IHC). Down-regulation of MT3-MMP was observed at protein level in 66.3% of ESCC specimens (by IHC, n = 86) for routine pathologic diagnosis, as well as at mRNA level in 63.3% of surgically resected ESCC tumors paired with surrounding nontumor tissues (by qPCR, n = 30). Notably, MT3-MMP down-regulation significantly correlated with lymph node metastasis and poor overall survival of patients with ESCC (median 5-year survival = 50.69 vs. 30.77 months for patients with MT3-MMP-negative and -positive ESCC, respectively). Mechanistically, MT3-MMP negatively regulated proliferation, colony formation, and migration of ESCC cells, in association with cell cycle arrest at G1, due to up-regulation of p21(Cip1) and p27(Kip1) . Together, as a tumor suppressor in ESCC, MT3-MMP down-regulation represents an unfavorable factor for prognosis of patients with ESCC.

Mesenchymal stem cells promote epithelial to mesenchymal transition and metastasis in gastric cancer though paracrine cues and close physical contact.

Mesenchymal stem cells (MSCs) have been shown to integrate into the tumor stroma; however, the precise mechanisms of this process are still elusive. In this study, the EMT phenotype and the enhanced metastatic ability of tumor cells were observed using transwell and trans-endothelial migration assays, respectively, as well as by using electron and laser confocal microscopy. Critical genes were screened and validated using gene arrays and clinical samples, and the changes at the protein level were examined both in vitro and in vivo. Cancer cells acquired an "activated" carcinoma-associated fibroblasts (CAFs) phenotype after being in close contact with MSCs and enhancing tumor metastasis and growth in vivo. Paracrine signals also induced EMT and promoted transwell and trans-endothelial migration, the changes were dependent on ß-catenin, MMP-16, snail and twist. Notably, the higher expression levels of ß-catenin and MMP-16 were correlated with tumor invasion and distant organ and lymph node metastases in intestinal type gastric cancer. MSCs within the tumor niche significantly facilitated tumor growth and metastasis by paracrine cues and close physical connection. This occurred partly through snail, twist and its downstream targets, specifically ß-catenin/MMP-16.

Attenuation of lung cancer stem cell tumorigenesis and metastasis by cisplatin.

PURPOSE: To investigate the effect of cisplatin on the growth and metastasis abilities of lung cancer stem cells (CSCs) via molecular imaging. MATERIALS AND METHODS: The expression changes of lung CSCs cell marker in A549-Luc-C8 human non-small-cell lung cancer (NSCLC) cell line with or without cisplatin treatment were detected by flow cytometry. The tumorigenesis and metastasis abilities of A549-Luc-C8 cells were monitored both in vitro and in vivo, and the mechanism was assessed by gene sequencing. RESULTS: About 1%-2% of CSCs were detected in A549-Luc-C8 cells and decreased CSCs percentage was observed after cisplatin treatment. Attenuated tumorigenesis and metastasis abilities of A549-Luc-C8 cells were found in cisplatin treated group. CONCLUSIONS: Decreased percentage of CSCs in A549-Luc-C8 cells can be induced by cisplatin treatment, which may partly be attributed to the attenuated expression of growth factors.

CacyBP/SIP enhances multidrug resistance of pancreatic cancer cells by regulation of P-gp and Bcl-2.

Our former report indicates that calcyclin-binding protein or Siah-1-interacting protein (CacyBP/SIP) is over-expressed in the SGC7901/ADR cell line. However, the potential role of CacyBP/SIP in the development of multidrug resistance (MDR) of pancreatic cancer is still uncertain. In this paper, we investigated the role of CacyBP/SIP in MDR of pancreatic cancer cells and its possible underlying mechanisms, and found that CacyBP/SIP was over-expressed in the Gemcitabine induced MDR pancreatic cancer cell PC-3/Gem compared with its parental cell PC-3. Up-regulation of CacyBP/SIP expression could enhance resistance of chemotherapy drugs on PC-3 cells and inhibit Adriamycin-induced apoptosis accompanied by decreased accumulation of intracellular Adriamycin. Furthermore, CacyBP/SIP could significantly up-regulate the expression of P-gp, Bcl-2, and the transcription of the MDR1 gene. In addition, the decrease of CacyBP/SIP expression using RNA interference or P-gp inhibitor could partially reverse CacyBP/SIP-mediated MDR. In brief, our study demonstrated that CacyBP/SIP could enhance the MDR phenotype of pancreatic cancer cells by increasing the expression of P-gp and Bcl-2, thus inhibiting apoptosis of pancreatic cancer cell.

Hepatic regeneration and the epithelial to mesenchymal transition.

Liver injuries are repaired by fibrosis and regeneration. The core stage is the repair response and fibrosis formation as a scar. The cause of overly-responsive scar formation and diminished regeneration, especially in liver fibrosis and cirrhosis, is still unknown. The epithelial to mesenchymal transition (EMT), a previously discovered mechanism, plays an important role in liver fibrosis and tumor metastasis. Recently, EMT has been found to be associated with liver and bile duct cell fibrosis. Analyzing the established models and chronic disease processes, we propose that EMT liver cells may also lose their regenerative capability due to phenotype changes and that the remaining liver cells may quickly lose their regenerative capability in liver fibrosis or cirrhosis. Recognizing these phenotype changes or transition cells may play an important role in targeting therapy to reverse fibrosis not only by disrupting the transition that is necessary to produce the extracellular matrix but also by restoring the regenerative capacity of EMT-like cells.

Molecular imaging of p53 signal pathway in lung cancer cell cycle arrest induced by cisplatin.

Cisplatin is a commonly employed chemotherapy drug for lung malignancy. However its efficacy is limited by acquired drug resistance and lacking of an in vivo real-time monitoring approach. The aim of this study is to investigate the effect of cisplatin on lung adenocarcinoma cell line p53-RE-Fluc/A549 in vivo via non-invasive reporter gene by molecular imaging. For this study, we employed p53-RE-Fluc/A549 cells that overexpressed a vector with three tandem repeats of p53 response element followed by the luciferase reporter gene. P53 activity was evaluated by optical imaging and verified by Western blot after cells were exposed to 10 µM cisplatin for 72 h. The cell cycle was mainly blocked at the S- and G2/M-phases after cisplatin treatment, whereas no significant change was observed in cell apoptotic index. Increased expression of p21 and Bcl-2 as well as decreased expression of Bax were observed after cisplatin treatment by Western blotting. Longitudinal in vivo bioluminescent imaging (BLI) revealed that the p53 activity was increased from 24 to 48 h after transient cisplatin treatment in p53-RE-Fluc/A549-bearing nude mice. RNA sequencing further revealed that cell cycle and p53 signaling pathway genes, such as E2F1, CCNA2, CDK1, and CCNE2 were significantly downregulated after long-term cisplatin treatment. Thus, our study showed that cisplatin exerts its cytotoxic effect through blockage of the cell cycle and may be partly regulated by the p53 signaling pathway. Furthermore, molecular imaging is a useful tool to investigate the mechanism and evaluate the effect of chemotherapy drugs both in vivo and in vitro.

Nuclear expression of Twist promotes lymphatic metastasis in esophageal squamous cell carcinoma.

Twist-1 protein (also called Twist) has been suggested to be involved in tumor epithelial-mesenchymal transition (EMT) related progression, however, the mechanism by which twist promotes lymph node metastasis is not fully understood. In the present study, we found that nuclear twist expression is clearly correlated with lymph node (LN) metastasis as determined by immunohistochemistry (IHC). A highly invasive EC109 cell subline, EC109-P, was established by repeated in vitro transwell isolations for the cell model. Immunofluorescence (IF) assay demonstrated that nuclear twist expression was markedly higher in the highly invasive EC109-P cell line when compared with EC109 and EC9706 cells. Based on our cell model, the function and mechanism by which twist regulates LN metastasis in ESCC was investigated. The results showed that the overexpression of Twist could significantly increase the invasion and VEGF-C expression of EC9706 cells, whereas the knockdown of twist expression results in the opposite effects. This finding was further strengthened by the results of the analysis of co-expression of twist and VEGF-C by IHC in ESCC clinical samples. In summary, our study indicates that nuclear twist plays an important role in ESCC lymphatic metastasis by increasing the expression of VEGF-C. The combination of twist and VEGF-C detection could be a reliable prediction of LN metastasis in ESCC.

Identification of cancer stem cells in vincristine preconditioned SGC7901 gastric cancer cell line.

Cancer stem cells (CSCs), or tumor initiating cells, are a subpopulation of cancer cells with self-renewal and differentiation properties. However, there has been no direct observation of the properties of gastric CSCs in vitro. Here we describe a vincristine (VCR)-preconditioning approach to obtain cancer stem-like cells (CSLCs) from the gastric cancer cell line SGC7901. The CSLCs displayed mesenchymal characteristics, including the up-regulated mesenchymal markers Snail, Twist, and vimentin, and the down-regulated epithelial marker E-cadherin. Using a Matrigel-based differentiation assay, CSLCs formed 2D tube-like and 3D complex lumen-like structures, which resembled differentiated gastric crypts. The characteristic of cellular differentiation was also found by transmission electron microscopy and up-regulation of gastrointestinal genes CDX2 and SOX2. We further showed that CSLCs could self-renew through significant asymmetric division compared with parent cells by tracing PKH-26, BrdU, and EDU label-retaining cells. In addition, these CSLCs also increased expression of CD44, CD90, and CXCR4 at the mRNA level, which was identified as novel targets. Furthermore, drug sensitivity assays and xenograft experiments demonstrated that the cells developed multi-drug resistance (MDR) and significant tumorigenicity in vivo. In summary, gastric CSCs were identified from VCR-preconditioned SGC7901 cell line, characterized by high tumorigenicity and the capacity for self-renewal and differentiation.

MiR-17 modulates osteogenic differentiation through a coherent feed-forward loop in mesenchymal stem cells isolated from periodontal ligaments of patients with periodontitis.

Chronic inflammatory diseases, such as rheumatoid arthritis and periodontitis, are the most common causes of bone tissue destruction. Recently, human periodontal ligament tissue-derived mesenchymal stem cells (PDLSCs), a population of multipotent stem cells, have been used to reconstruct tissues destroyed by chronic inflammation. However, the impact of the local inflammatory microenvironment on tissue-specific stem cells and the mechanisms controlling the effects of the local inflammatory environment remain poorly understood. In this study, we found that the multidifferentiation potential of mesenchymal stem cells (MSCs) isolated from periodontitis-affected periodontal ligament tissue (P-PDLSCs) was significantly lower than that of MSCs isolated from healthy human periodontal ligament tissue (H-PDLSCs). Inflammation in the microenvironment resulted in an inhibition of miR-17 levels, and a perturbation in the expression of miR-17 partly reversed the differentiation potential of PDLSCs in this microenvironment. Furthermore, inflammation in the microenvironment promoted the expression of Smad ubiquitin regulatory factor one (Smurf1), an important negative regulator of MSC osteogenic differentiation. Western blotting and 3' untranslated regions (3'-UTR) reporter assays confirmed that Smurf1 is a direct target of miR-17 in PDLSCs. Our data demonstrate that excessive inflammatory cytokine levels, miR-17, and Smurf1 were all involved in a coherent feed-forward loop. In this circuit, inflammatory cytokines led to direct activation of Smurf1 and downregulation of miR-17, thereby increasing degradation of Smurf1-mediated osteoblast-specific factors. The elucidation of the molecular mechanisms governing MSC osteogenic differentiation in a chronic inflammatory microenvironment could provide us with a better knowledge of chronic inflammatory disorder and improve stem cell-mediated inflammatory bone disease therapy.

MicroRNA let-7f inhibits tumor invasion and metastasis by targeting MYH9 in human gastric cancer.

BACKGROUND: MicroRNAs (miRNAs) are important regulators that play key roles in tumorigenesis and tumor progression. A previous report has shown that let-7 family members can act as tumor suppressors in many cancers. Through miRNA array, we found that let-7f was downregulated in the highly metastatic potential gastric cancer cell lines GC9811-P and SGC7901-M, when compared with their parental cell lines, GC9811 and SGC7901-NM; however, the mechanism was not clear. In this study, we investigate whether let-7f acts as a tumor suppressor to inhibit invasion and metastasis in gastric cancers. METHODOLOGY/PRINCIPAL: Real-time PCR showed decreased levels of let-7f expression in metastatic gastric cancer tissues and cell lines that are potentially highly metastatic. Cell invasion and migration were significantly impaired in GC9811-P and SGC7901-M cell lines after transfection with let-7f-mimics. Nude mice with xenograft models of gastric cancer confirmed that let-7f could inhibit gastric cancer metastasis in vivo after transfection by the lentivirus pGCsil-GFP- let-7f. Luciferase reporter assays demonstrated that let-7f directly binds to the 3'UTR of MYH9, which codes for myosin IIA, and real-time PCR and Western blotting further indicated that let-7f downregulated the expression of myosin IIA at the mRNA and protein levels. CONCLUSIONS/SIGNIFICANCE: Our study demonstrated that overexpression of let-7f in gastric cancer could inhibit invasion and migration of gastric cancer cells through directly targeting the tumor metastasis-associated gene MYH9. These data suggest that let-7f may be a novel therapeutic candidate for gastric cancer, given its ability to reduce cell invasion and metastasis.

CacyBP/SIP protein promotes proliferation and G1/S transition of human pancreatic cancer cells.

Calcyclin-binding protein or Siah-1-interacting protein (CacyBP/SIP), a component of the ubiquitin-mediated proteolysis, could participate in beta-catenin degradation, which was found to be related to the malignant phenotypes of pancreatic cancer previously. However, the role of CacyBP/SIP itself in pancreatic cancer has not been investigated. In the present study, CacyBP/SIP expression was assayed and manipulated to reveal the potential mechanism in pancreatic cancer carcinogenesis. Here, we show that CacyBP/SIP is over-expressed in pancreatic cancer cells. Down-regulation of CacyBP/SIP by small interference RNA (siRNA) severely suppresses the proliferation and tumorigenesis in pancreatic cancer. G1/S transition arrest induced by inhibition of CacyBP/SIP is at least partly mediated by down-regulation of Cyclin E and CDK2 as well as up-regulation of p27 and Rb. Collectively, CacyBP/SIP as an enhancer of pancreatic cancer malignance might develop into another possible therapeutic target.

MiR-150 promotes gastric cancer proliferation by negatively regulating the pro-apoptotic gene EGR2.

Accumulating evidence suggests small non-coding RNAs (microRNAs) play important roles in human cancer progression. In the present study, we found miR-150 was overexpressed in gastric cancer cell lines and tissues. Ectopic expression of miR-150 promoted tumorigenesis and proliferation of gastric cancer cells. Luciferase reporter assay demonstrated that EGR2 was a direct target of miR-150. Collectively, our study demonstrated that overexpression of miR-150 in gastric cancer could promote proliferation and growth of cancer cells at least partially through directly targeting the tumor-suppressor EGR2, suggesting a potential strategy for the development of miRNA-based treatment of gastric cancer.