Previous reports have suggested that some probiotics inhibit tumorigenesis and cancer progression. However, the molecules involved have not yet been identified. Here, we show that the culture supernatant of Lactobacillus casei ATCC334 has a strong tumour-suppressive effect on colon cancer cells. Using mass spectrometry, we identify ferrichrome as a tumour-suppressive molecule produced by L. casei ATCC334. The tumour-suppressive effect of ferrichrome is greater than that of cisplatin and 5-fluorouracil, and ferrichrome has less of an effect on non-cancerous intestinal cells than either of those agents. A transcriptome analysis reveals that ferrichrome treatment induces apoptosis, which is mediated by the activation of c-jun N-terminal kinase (JNK). Western blotting indicates that the induction of apoptosis by ferrichrome is reduced by the inhibition of the JNK signalling pathway. This we demonstrate that probiotic-derived ferrichrome exerts a tumour-suppressive effect via the JNK signalling pathway.

RNA-based therapeutics is a promising approach for curing intractable diseases by manipulating various cellular functions. For eliciting RNA (i.e., mRNA and siRNA) functions successfully, the RNA in the extracellular space must be protected and it must be delivered to the cytoplasm. In this study, the development of a self-degradable lipid-like material that functions to accelerate the collapse of lipid nanoparticles (LNPs) and the release of RNA into cytoplasm is reported. The self-degradability is based on a unique reaction "Hydrolysis accelerated by intra-Particle Enrichment of Reactant (HyPER)." In this reaction, a disulfide bond and a phenyl ester are essential structural components: concentrated hydrophobic thiols that are produced by the cleavage of the disulfide bonds in the LNPs drive an intraparticle nucleophilic attack to the phenyl ester linker, which results in further degradation. An oleic acid-scaffold lipid-like material that mounts all of these units (ssPalmO-Phe) shows superior transfection efficiency to nondegradable or conventional materials. The insertion of the aromatic ring is unexpectedly revealed to contribute to the enhancement of endosomal escape. Since the intracellular trafficking is a sequential process that includes cellular uptake, endosomal escape, the release of mRNA, and translation, the improvement in each process synergistically enhances the gene expression.

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Hypoxia-inducible factor 1 (HIF-1) is involved in tumor progression/metastasis and activated in various cancers. Here we show that HIF-1A, which plays a major role in HIF-1 activation, is overexpressed in preneoplastic hepatocytic lesions from a very early stage during hepatocarcinogenesis in mice and man. Transcriptional targets of HIF-1, such as vascular endothelial growth factor, glut-1, c-met, and insulinlike growth factor II (IGF-II), were also overexpressed in mouse lesions. Oxygen tension within the lesions was not different from that of the normal hepatic tissues, indicating that HIF-1A expression was independent of hypoxia. On the other hand, Akt, the pathway of which can up-regulate HIF-1A expression, was activated in the mouse lesions, whereas HIF-1A was markedly down-regulated in the mouse hepatocellular carcinoma (HCC) cell lines after treatment with a phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002, indicating that HIF-1A expression is dependent on PI3K/Akt signaling. Conversely, HIF-1A knockdown by short interfering RNA in the HCC cell line resulted in decreased expression of activated Akt together with the HIF-1 target genes, indicating that Akt activation is reversely dependent on HIF-1 activation. Treating the HCC cells with IGF-II or epidermal growth factor (EGF) up-regulated both phospho-Akt and HIF-1A, whereas inhibition of IGF-II or EGF signaling down-regulated them both, suggesting that IGF-II and EGF can, at least in part, mediate the activation of Akt and HIF-1A. However, Akt was not activated by IGF-II or EGF in the HIF-1A knockdown cells, indicating that expression of the HIF-1 target genes is necessary for the Akt activation. These findings suggest that the reciprocal activation of PI3K/Akt signaling and HIF-1A may be important in the progression of hepatocarcinogenesis.

Transpapillary brushing cytology and forceps biopsy could be performed in a short time. The diagnosis rate was high, and the incidence of complication was low, having no influence on subsequent biliary drainage.