Skin stem cells can regenerate epidermal appendages; however, hair follicles (HF) lost as a result of injury are barely regenerated. Here we show that macrophages in wounds activate HF stem cells, leading to telogen–anagen transition (TAT) around the wound and de novo HF regeneration, mostly through TNF signalling. Both TNF knockout and overexpression attenuate HF neogenesis in wounds, suggesting dose-dependent induction of HF neogenesis by TNF, which is consistent with TNF-induced AKT signalling in epidermal stem cells in vitro. TNF-induced β-catenin accumulation is dependent on AKT but not Wnt signalling. Inhibition of PI3K/AKT blocks depilation-induced HF TAT. Notably, Pten loss in Lgr5+ HF stem cells results in HF TAT independent of injury and promotes HF neogenesis after wounding. Thus, our results suggest that macrophage-TNF-induced AKT/β-catenin signalling in Lgr5+ HF stem cells has a crucial role in promoting HF cycling and neogenesis after wounding.

Inflammation has an important role in cancer development through various mechanisms. It has been shown that dysregulation of microRNAs (miRNAs) that function as oncogenes or tumor suppressors contributes to tumorigenesis. However, the relationship between inflammation and cancer-related miRNA expression in tumorigenesis has not yet been fully understood. Using K19-C2mE and Gan mouse models that develop gastritis and gastritis-associated tumors, respectively, we found that 21 miRNAs were upregulated, and that 29 miRNAs were downregulated in gastric tumors in an inflammation-dependent manner. Among these miRNAs, the expression of miR-7, a possible tumor suppressor, significantly decreased in both gastritis and gastric tumors. Moreover, the expression of miR-7 in human gastric cancer was inversely correlated with the levels of interleukin-1b and tumor necrosis factor-a, suggesting that miR-7 downregulation is related to the severity of inflammatory responses. In the normal mouse stomach, miR-7 expression was at a basal level in undifferentiated gastric epithelial cells, and was induced during differentiation. Moreover, transfection of a miR-7 precursor into gastric cancer cells suppressed cell proliferation and soft agar colony formation. These results suggest that suppression of miR-7 expression is important for maintaining the undifferentiated status of gastric epithelial cells, and thus contributes to gastric tumorigenesis. Although epigenetic changes were not found in the CpG islands around miR-7-1 of gastritis and gastric tumor cells, we found that activated macrophage-derived small molecule(s) (o3 kDa) are responsible for miR-7 repression in gastric cancer cells. Furthermore, the miR-7 expression level significantly decreased in the inflamed gastric mucosa of Helicobacter-infected mice, whereas it increased in the stomach of germfree K19-C2mE and Gan mice wherein inflammatory responses were suppressed.Taken together, these results indicate that downregulation of tumor suppressor miR-7 is a novel mechanism by which the inflammatory response promotes gastric tumorigenesis.

Light-inducible gene switches represent a key strategy for the precise manipulation of cellular events in fundamental and applied research. However, the performance of widely used gene switches is limited due to low tissue penetrance and possible phototoxicity of the light stimulus. To overcome these limitations, we engineer optogenetic synthetic transcription factors to undergo liquid-liquid phase separation in close spatial proximity to promoters. Phase separation of constitutive and optogenetic synthetic transcription factors was achieved by incorporation of intrinsically disordered regions. Supported by a quantitative mathematical model, we demonstrate that engineered transcription factor droplets form at target promoters and increase gene expression up to fivefold. This increase in performance was observed in multiple mammalian cells lines as well as in mice following in situ transfection. The results of this work suggest that the introduction of intrinsically disordered domains is a simple yet effective means to boost synthetic transcription factor activity.

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The long noncoding RNA cancer susceptibility 9 (CASC9) has been reported to be a pivot modulator in growth and metastasis of breast cancer, liver cancer, esophageal squamous cell carcinoma, lung adenocarcinoma, gastric cancer, and nasopharyngeal cancer. However, its potential roles in ovarian cancer remain unclear. In this study, we aimed at its functions and molecular mechanism in ovarian cancer progression. We showed that CASC9 was highly expressed in ovarian cancer tissues and cell lines. An elevated level of CASC9 predicts an unfavorable prognosis in patients with ovarian cancer. Loss‐of‐function and gain‐of‐function assays illustrated that CASC9 promotes ovarian cancer cell proliferation, migration, and invasion in vitro, and accelerates tumor growth in vivo. We showed that CASC9 works as a competing endogenous RNA (ceRNA) for miR‐758‐3p which targets LIN7A. CASC9 inhibits the level of miR‐758‐3p, and in turn stimulates LIN7A expression in ovarian cancer. Overexpression of LIN7A reverses the suppressive roles of CASC9 depletion on ovarian cancer. In sum, our findings reveal a novel undefined regulatory signaling pathway, namely CASC9/miR‐758‐3p/LIN7A axis, involved in ovarian cancer progression.

Cyclooxygenase-2 (COX-2) plays an important role in tumorigene-sis through prostaglandin E 2 (PGE 2) biosynthesis. It has been shown by in vitro studies that PGE 2 signaling transactivates epi-dermal growth factor receptor (EGFR) through an intracellular mechanism. However, the mechanisms underlying PGE 2-induced EGFR activation in in vivo tumors are still not fully understood. We previously constructed transgenic mice that develop gastric tumors caused by oncogenic activation and PGE 2 pathway induction. Importantly, expression of EGFR ligands, epiregulin, amphi-regulin, heparin-binding EGF-like growth factor, and betacellulin, as well as a disintegrin and metalloproteinases (ADAMs), ADAM8, ADAM9, ADAM10, and ADAM17 were significantly increased in the mouse gastric tumors in a PGE 2 pathway-dependent manner. These ADAMs can activate EGFR by ectodomain shedding of EGFR ligands. Notably, the extensive induction of EGFR ligands and ADAMs was suppressed by inhibition of the PGE 2 receptor EP4. Moreover, EP4 signaling induced expression of amphiregulin and epiregulin in activated macrophages, whereas EP4 pathway was required for basal expression of epiregulin in gastric epithelial cells. In contrast, ADAMs were not induced directly by PGE 2 in these cells, suggesting indirect mechanism possibly through PGE 2-associated inflammatory responses. These results suggest that PGE 2 signaling through EP4 activates EGFR in gastric tumors through global induction of EGFR ligands and ADAMs in several cell types either by direct or indirect mechanism. Importantly, gastric tumorigenesis of the transgenic mice was significantly suppressed by combination treatment with EGFR and COX-2 inhibitors. Therefore, it is possible that inhibition of both COX-2 ⁄ PGE 2 and EGFR pathways represents an effective strategy for preventing gastric cancer. (Cancer Sci 2011; 102: 713-719) I t has been established that induction of cyclooxygenase 2 (COX-2) plays an important role in cancer development. (1,2) Genetic mouse model studies indicated that prostaglandin E 2 (PGE 2), a downstream products of COX-2, plays a key role in intestinal tumorigenesis, (3-5) suggesting that the PGE 2 pathway is a possible target for the chemoprevention. On the other hand, epidermal growth factor receptor (EGFR) signaling is also an important target for cancer prevention. (6) Inhibition of EGFR signaling in Apc Min mice, a model of familial adenomatous polyposis, significantly suppresses intestinal polyposis. (7-9) Importantly, combination treatment using an EGFR inhibitor with non-steroidal anti-inflammatory drugs or a COX-2 inhibitor dramatically suppresses intestinal tumorigenesis. (8,9) It has been shown by in vitro experiments that PGE 2 signaling trans-activates EGFR through activation of cSrc (10,11) or MMPs (12) , as well as induction of amphiregulin, an EGFR ligand (13,14) or tumor necrosis factor-a converting enzyme ⁄ a disintegrin and metalloproteinase 17 (TACE/ADAM17), a shedding enzyme for amphiregulin. (15) However, the mechanism responsible for the act...

Abstract. Previous studies have demonstrated that long non-coding RNAs (lncRNAs) serve an important role in carcinogenesis. BC200 is a lncRNA that is reportedly associated with ovarian cancer. The aim of the present study was to investigate this potential association between BC200 and ovarian cancer, and to subsequently analyze the biological function of BC200 in the disease. BC200 expression was compared in ovarian cancer tissue and normal ovarian tissue samples through the use of quantitative polymerase chain reaction. To allow the biological function of BC200 in ovarian cancer to be analyzed, small interfering RNA was used to knock down the expression of BC200 in SKOV3 and A2780 ovarian cancer cells. The proliferative, invasive and migratory abilities of the cells were identified by means of cell counting kits and Transwell assays. Carboplatin was also used to treat the ovarian cancer cells, and a luminescent cell viability assay was subsequently used to detect the sensitivity of the cells to the carboplatin. The results demonstrated that BC200 expression was reduced in ovarian cancer compared with normal ovarian tissue samples. In the SKOV3 and A2780 cells, BC200 exerted no effect on invasive or migratory ability, however, the inhibition of BC200 was demonstrated to promote cell proliferation. Additionally, it was observed that carboplatin induced BC200 expression in the cell lines, and that the inhibition of BC200 decreased the sensitivity of the cells to the drug. BC200 is therefore likely to have a tumor suppressive function in ovarian cancer by affecting cell proliferation. Furthermore, BC200 appears to serve a role in the mediation of carboplatin-induced ovarian cancer cell death.

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