RNA methylation has emerged as a fundamental process in epigenetic regulation. Accumulating evidences indicate that RNA methylation is essential for many biological functions, and its dysregulation is associated with human cancer progression, particularly in gastrointestinal cancers. RNA methylation has a variety of biological properties, including N6-methyladenosine (m6A), 2-O-dimethyladenosine (m6Am), N1-methyladenosine (m1A), 5-methylcytosine (m5C) and 7-methyl guanosine (m7G). Dynamic and reversible methylation on RNA is mediated by RNA modifying proteins called “writers” (methyltransferases) and “erasers” (demethylases). “Readers” (modified RNA binding proteins) recognize and bind to RNA methylation sites, which influence the splicing, stability or translation of modified RNAs. Herein, we summarize the biological functions and mechanisms of these well-known RNA methylations, especially focusing on the roles of m6A in gastrointestinal cancer development.

β-Hydroxybutyric acid (BHBA) has neuroprotective effects, but the underlying molecular mechanisms are unclear. Microglial activation plays an important role in neurodegenerative diseases by producing several proinflammatory enzymes and proinflammatory cytokines. The current study investigates the potential mechanisms whereby BHBA affects the expression of potentially proinflammatory proteins by cultured murine microglial BV-2 cells stimulated with lipopolysaccharide (LPS). The results showed that BHBA significantly reduced LPS-induced protein and mRNA expression levels of iNOS, COX-2, TNF-α, IL-1β, and IL-6. Blocking of GPR109A by PTX resulted in a loss of this anti-inflammatory effect in BV-2 cells. Western blot analysis showed that BHBA reduced LPS-induced degradation of IκB-α and translocation of NF-κB, while no effect was observed on MAPKs phosphorylation. All results imply that BHBA significantly reduces levels of proinflammatory enzymes and proinflammatory cytokines by inhibition of the NF-κB signaling pathway but not MAPKs pathways, and GPR109A is essential to this function. Overall, these data suggest that BHBA has a potential as neuroprotective drug candidate in neurodegenerative diseases.

Generation of T lymphocytes with reactivity against cancer is a prerequisite for effective adoptive cellular therapies. We established a protocol for tumor-infiltrating lymphocytes (TILs) from patients with pancreatic ductal adenocarcinoma. Tumor samples from 17 pancreatic cancer specimens were cultured with cytokines (IL-2, IL-15, and IL-21) to expand TILs. After 10 days of culture, TILs were stimulated with an anti-CD3 antibody (OKT3) and irradiated allogeneic peripheral blood mononuclear cells. Reactivity of TILs against tumor-associated antigens (mesothelin, survivin, or NY-ESO-1) was detected by intracellular cytokine production by flow cytometry. Cytotoxicity was measured using a Chromium 51 release assay, and reactivity of TILs against autologous tumor cells was detected by INF-[gamma] production (ELISA). TIL composition was tested by CD45RA, CCR7, 4-1BB, LAG-3, PD-1, TIM3, and CTLA-4 marker analysis. TCR V[beta] was determined by flow cytometry and TCR clonality was gauged measuring the CDR3 region length by PCR analysis and subsequent sequencing. We could reliably obtain TILs from 17/17 patients with a majority of CD8(+) T cells. CD3(+)CD8(+), CD3(+)CD4(+), and CD3(+)CD4(-)CD8(-)[double-negative (DN) T cells] resided predominantly in central (CD45RA(-)CCR7(+)) and effector (CD45RA-CCR7-) memory subsets. CD8(+) TILs tested uniformly positive for LAG-3 (about 100%), whereas CD4(+) TILs showed only up to 12% LAG-3(+) staining and PD-1 showed a broad expression pattern in TILs from different patients. TILs from individual patients recognized strongly (up to 11.9% and 8.2% in CD8(+)) NY-ESO-1, determined by ICS, or mesothelin, determined respectively by TNF-[alpha] and IFN-[gamma] production. Twelve of 17 of CD8(+) TILs showed preferential expansion of certain TCR V[beta] families (eg, 99.2% V[beta]13.2 in CD8(+) TILs, 77% in the V[beta]1, 65.9% in the V[beta]22, and 63.3% in the V[beta]14 family). TCR CDR3 analysis exhibited monoclonal or oligoclonal TCRs, some of them (eg, CD8(+) V[beta]13.2) reacting strongly against autologous tumor defined by INF-[gamma] production or by cytotoxicity. We have optimized methods for generating pancreatic cancer–specific TILs that can be used for adoptive cellular therapy of patients with pancreatic cancer.

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Hyperactivation of Wnt/β-catenin signaling is one of the major causes of human colorectal cancer (CRC). A hallmark of Wnt signaling is the nuclear accumulation of β-catenin. Although β-catenin nuclear import and export have been widely investigated, the underlying mechanism of β-catenin's nuclear retention remains largely unknown. Here, we report that Twa1/Gid8 is a key nuclear retention factor for β-catenin during Wnt signaling and colorectal carcinogenesis. In the absence of Wnt, Twa1 exists together with β-catenin in the Axin complex and undergoes ubiquitination and degradation. Upon Wnt signaling, Twa1 translocates into the nucleus, where it binds and retains β-catenin. Depletion of Twa1 attenuates Wnt-stimulated gene expression, dorsal development of zebrafish embryos and xenograft tumor growth of CRC cells. Moreover, nuclear Twa1 is significantly upregulated in human CRC tissues, correlating with the nuclear accumulation of β-catenin and poor prognosis. Thus, our results identify Twa1 as a previously undescribed regulator of the Wnt pathway for promoting colorectal tumorigenesis by facilitating β-catenin nuclear retention.

The aim of this study was to investigate the anti-inflammatory effect of IL-21 on LPS-induced mouse peritoneal macrophages. The results showed that IL-21 significantly inhibited LPS-induced mRNA expression of IL-1β, TNF-α, and IL-6 in macrophages, but not of IFN-γ, IL-10, CCL5, or CXCL2. ELISA analysis showed that IL-21 also suppressed LPS-induced production of TNF-α and IL-6 in culture supernatants. Western blot analysis showed that IL-21 clearly inhibited ERK and IκBα phosphorylation and NF-κB translocation in LPS-stimulated macrophages, but it increased STAT3 phosphorylation. Flow cytometric and Western blot analysis showed that IL-21 decreased M1 macrophages surface markers expression of CD86, iNOS, and TLR4 in LPS-stimulated cells. All results suggested that IL-21 decreases IL-6 and TNF-α production via inhibiting the phosphorylation of ERK and translocation of NF-κB and promotes a shift from the M1 to M2 macrophage phenotype by decreasing the expression of CD86, iNOS, and TLR4 and by increasing STAT3 phosphorylation in LPS-stimulated cells.

Neural stem and progenitor cells (NSPCs) can be isolated from the fetal or adult brain and expanded in culture for potential use in basic research, drug discovery and cell therapy. In the present study, two culture systems have been commonly used to maintain and expand NSPCs isolated from mammalian CNS: neurosphere and adhesive substrate-bound monolayer culture. NSPCs were isolated from the neuroepithelium of E14 embryonic rat cerebral cortex and maintained and expanded on fibronectin substrates or within neurospheres in serum-free medium. Ultrastructural study under transmission electron microscope revealed similar characteristics of immature morphology of NSPCs in adherent and neurosphere cultures. NSPCs cultured on adherent substrates and within neurospheres shared the properties of self-renewal and multipotency, but little is known about proliferation capacity and passaging potential of adherent NSPCs compared to neurosphere culture. We found that the self-renewal capacity of NSPCs in adherent culture was higher than that in neurosphere culture in the P1 and P3 passages, and reduced after the P5 passage. At the same time, comparative analysis using BrdU incorporation and immunostaining for nestin indicated that NSPCs grew significantly faster in primary cultures on adherent substrates than within neurospheres. Whereas, NSPCs in adherent culture could not maintain such robust growth for more than 6 passages. The growth of NSPCs within neurospheres was slower than that in adherent culture, but increased steadily and could be maintained for more than 10 passages. These data provide useful information for large scale in vitro expansion of NSPCs required by potential drug screening and cell therapy.

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