5-Fluorouracil (FU) is a chemotherapeutic agent commonly used against esophageal cancer. Recently, interferons (IFNs) have
been administered together with cytotoxic chemotherapy to patients with this ...cancer, although the mechanisms of synergy are
unknown. We reconsidered the mechanisms for the effects of 5-FU in this context, aiming to refine combination therapy. After
three cell lines (T.T, TE-2, and TE-6), derived from human esophageal squamous cell carcinoma (SCC), were exposed to 5-FU,
the expression profiles were analyzed using high-density oligonucleotide microarrays representing about 12,000 genes. Among
them, three IFN-related genes, an IFN receptor gene (IFNAR2) and two IFN-stimulated genes (ISG15K, ISG-54K), that were up-regulated
following addition of 5-FU, were investigated. Up-regulation was confirmed by RT-PCR. Based on these results, the antitumor
effects of exposure to 5-FU simultaneously with IFN-α, β and -γ were investigated. The growth of esophageal SCC cells with
5-FU was suppressed synergistically or semi-additively by IFN-α and β, but not by IFN-γ. These findings indicated that 5-FU
stimulated IFN pathways in esophageal SCC cells following up-regulation of the IFN type I receptor. A combination of 5-FU
and an IFN, therefore, may be particularly efficacious in esophageal cancer.
Dysregulated G protein-coupled receptor signaling is involved in the formation and progression of human cancers. The heterotrimeric G protein Gα13 is highly expressed in various cancers and regulates ...diverse cancer-related transcriptional networks and cellular functions by activating Rho. Herein, we demonstrate that increased expression of Gα13 promotes cell proliferation through activation of Rho and the transcription factor AP-1 in human endometrial cancer. Of interest, the RhoGTPase activating protein (RhoGAP), ARHGAP35 is frequently mutated in human endometrial cancers. Among the 509 endometrial cancer samples in The Cancer Genome Atlas database, 108 harbor 152 mutations at 126 different positions within ARHGAP35, representing a somatic mutation frequency of 20.2%. We evaluated the effect of 124 tumor-derived ARHGAP35 mutations on Gα13-mediated Rho and AP-1 activation. The RhoGAP activity of ARHGAP35 was impaired by 55 of 124 tumor-derived mutations, comprised of 23 nonsense, 15 frame-shift, 15 missense mutations, and two in-frame deletions. Considering that ARHGAP35 is mutated in >2% of all tumors, it ranks among the top 30 most significantly mutated genes in human cancer. Our data suggest potential roles of ARHGAP35 as an oncogenic driver gene, providing novel therapeutic opportunities for endometrial cancer.
We studied the development and structure of the unusual trichotomous branching of Edgeworthia chrysantha. Three "branch primordia" are formed sequentially on the shoot apex of a main axis and develop ...into trichotomous branching. The branch primordia are clearly distinguishable from the typical axillary buds of other angiosperms; they develop much more rapidly than axillary buds, and the borders between the branch primordia and shoot apex of the main axis are anatomically unclear. Furthermore, at a later stage, leaves subtending the branch primordia produce typical axillary buds. These results suggest that the trichotomous branching in this species involves the division of the shoot apical meristem. Expression analysis of genes involved in branching or maintenance of the shoot apical meristem in this species should clarify the control mechanism of this novel branching pattern in angiosperms. We also observed the phyllotactic patterns in trichotomous branching and have related these patterns to the shoot system as a whole.
The prognosis of patients with high‐grade or advanced‐stage endometrial cancer remains poor. As cancer stem‐like cells (CSCs) are thought to be associated with endometrial cancers, it is essential to ...investigate the molecular mechanisms that regulate endometrial CSCs. Dual‐specificity phosphatase 6 (DUSP6) functions as a negative‐feedback regulator of MAPK–ERK1/2 signaling, but its role in endometrial cancer remains unknown. We investigated whether DUSP6 is involved in cancer cell stemness using endometrial cancer cell lines and specimens from endometrial cancer patients. DUSP6 induced the expression of CSC‐related genes including ALDH1, Nanog, SOX2 and Oct4A, increased the population of cells in the G0/G1 phase, and promoted sphere formation ability. DUSP6 knockdown resulted in reduced cell invasion and metastasis, whereas DUSP6 overexpression inhibited apoptosis under serum‐free conditions. Moreover, DUSP6 decreased phosphorylated ERK1/2 and increased phosphorylated Akt levels, which potentially induces CSC features. In patients with endometrial cancers, DUSP6 expression was determined using immunohistochemistry, and based on the results, the patients were dichotomized into high‐ and low‐DUSP6‐expression groups. Progression‐free survival and overall survival were significantly shorter in the high‐DUSP6‐expression group. These results suggest that DUSP6 has potential value as a biomarker of CSCs and as a target of therapies designed to eliminate CSCs in endometrial cancer.
What's new?
Although cancer stem‐like cells (CSCs) are involved in human endometrial cancers, the underlying molecular mechanisms and biomarkers for CSCs in endometrial cancers remain elusive. Here, the authors found that DUSP6 plays an important role in regulating endometrial CSC phenotypes by increasing self‐renewal ability and starvation resistance. DUSP6 expression was required for inducing invasion and metastasis and resulted in ERK1/2 dephosphorylation and Akt phosphorylation, which potentially contribute to the promotion of CSC phenotypes. As DUSP6 expression was also positively associated with worse progression‐free and overall survival, DUSP6 represents a potential biomarker for endometrial CSCs and a therapeutic target in endometrial cancers.
Dendritic cells (DCs) induce immunity and immunological tolerance as APCs. It has been shown that DCs secreting IL-10 induce IL-10(+) Tr1-type regulatory T (Treg) cells, whereas Foxp3-positive Treg ...cells are expanded from naive CD4(+) T cells by coculturing with mature DCs. However, the regulatory mechanism of expansion of Foxp3(+) Treg cells by DCs has not been clarified. In this study, we demonstrated that suppressors of cytokine signaling (SOCS)-3-deficient DCs have a strong potential as Foxp3(+) T cell-inducing tolerogenic DCs. SOCS3(-/-) DCs expressed lower levels of class II MHC, CD40, CD86, and IL-12 than wild-type (WT)-DCs both in vitro and in vivo, and showed constitutive activation of STAT3. Foxp3(-) effector T cells were predominantly expanded by the priming with WT-DCs, whereas Foxp3(+) Treg cells were selectively expanded by SOCS3(-/-) DCs. Adoptive transfer of SOCS3(-/-) DCs reduced the severity of experimental autoimmune encephalomyelitis. Foxp3(+) T cell expansion was blocked by anti-TGF-beta Ab, and SOCS3(-/-) DCs produced higher levels of TGF-beta than WT-DCs, suggesting that TGF-beta plays an essential role in the expansion of Foxp3(+) Treg cells. These results indicate an important role of SOCS3 in determining on immunity or tolerance by DCs.
Innate γδ T cells expressing Vγ6 produce IL-17A at an early stage following infection with Mycobacterium bovis Bacillus Calmette-Guérin (BCG). In this study, we used IL-21 receptor knockout (IL-21R ...KO) mice and IL-21-producing recombinant BCG mice (rBCG-Ag85B-IL-21) to examine the role of IL-21 in the regulation of IL-17A-producing innate γδ T-cell response following BCG infection. IL-17A-producing Vγ6+ γδ T cells increased in the peritoneal cavity of IL-21R KO mice more than in wild type mice after BCG infection. In contrast, the number of IL-17A-producing Vγ6+ γδ T cells was significantly lower after inoculation with rBCG-Ag85B-IL-21 compared with control rBCG-Ag85B. Notably, exogenous IL-21 selectively induced apoptosis of IL-17A-producing Vγ6+ γδ T cells via Bim. Thus, these results suggest that IL-21 acts as a potent inhibitor of a IL-17A-producing γδ T-cell subset during BCG infection.
Dysregulated G protein-coupled receptor signaling is involved in the formation and progression of human cancers. The heterotrimeric G protein Gα
is highly expressed in various cancers and regulates ...diverse cancer-related transcriptional networks and cellular functions by activating Rho. Herein, we demonstrate that increased expression of Gα
promotes cell proliferation through activation of Rho and the transcription factor AP-1 in human endometrial cancer. Of interest, the RhoGTPase activating protein (RhoGAP), ARHGAP35 is frequently mutated in human endometrial cancers. Among the 509 endometrial cancer samples in The Cancer Genome Atlas database, 108 harbor 152 mutations at 126 different positions within ARHGAP35, representing a somatic mutation frequency of 20.2%. We evaluated the effect of 124 tumor-derived ARHGAP35 mutations on Gα
-mediated Rho and AP-1 activation. The RhoGAP activity of ARHGAP35 was impaired by 55 of 124 tumor-derived mutations, comprised of 23 nonsense, 15 frame-shift, 15 missense mutations, and two in-frame deletions. Considering that ARHGAP35 is mutated in >2% of all tumors, it ranks among the top 30 most significantly mutated genes in human cancer. Our data suggest potential roles of ARHGAP35 as an oncogenic driver gene, providing novel therapeutic opportunities for endometrial cancer.
The membrane microdomains known as lipid rafts have been shown to act as platforms for the initiation of various receptor signals. Through proteomic analysis, we have identified a novel protein ...termed Raftlin (raft-linking protein) as a major protein in lipid rafts. To determine the physiological and immunological functions of Raftlin in mammals, we generated Raftlin-deficient mice, as well as Raftlin-transgenic (Tg) mice. Although Raftlin was originally identified in B cells, we observe no severe abnormalities in the B cells of these mice, presumably due to a high expression of Raftlin-homologue (Raftlin-2). T cells, in contrast, expressed a substantial amount of Raftlin but no Raftlin-2. In Raftlin-deficient mice, T cell-dependent Ab production was reduced, and experimental autoimmune encephalomyelitis, a Th17-dependent autoimmune disease model, was ameliorated. In Raftlin-Tg mice, in contrast, Ab production was enhanced and experimental autoimmune encephalomyelitis was more severe. Cytokine production, especially that of IL-17, was reduced in Raftlin-deficient T cells, while it was enhanced in Raftlin-Tg T cells. We found that these changes were associated with the strength of the TCR-mediated signals. Importantly, localization of Lck protein in the lipid rafts was enhanced by Raftlin overexpression and reduced by Raftlin deficiency. These data indicate that Raftlin modulates TCR signals and is necessary for the fine-tuning of T cell-mediated immune responses.
Innate gamma delta T cells expressing V gamma 6 produce IL-17A at an early stage following infection with Mycobacterium bovi s Bacillus Calmette-Guerin (BCG). In this study, we used IL-21 receptor ...knockout (IL-21R KO) mice and IL-21-producing recombinant BCG mice (rBCG-Ag85B-IL-21) to examine the role of IL-21 in the regulation of IL-17A-producing innate gamma delta T-cell response following BCG infection. IL-17A-producing V gamma 6 + gamma delta T cells increased in the peritoneal cavity of IL-21R KO mice more than in wild type mice after BCG infection. In contrast, the number of IL-17A-producing V gamma 6 + gamma delta T cells was significantly lower after inoculation with rBCG-Ag85B-IL-21 compared with control rBCG-Ag85B. Notably, exogenous IL-21 selectively induced apoptosis of IL-17A-producing V gamma 6 + gamma delta T cells via Bim. Thus, these results suggest that IL-21 acts as a potent inhibitor of a IL-17A-producing gamma delta T-cell subset during BCG infection.
The present study was designed to investigate the rewarding effect, G‐protein activation and dopamine (DA) release following partial sciatic nerve ligation in the rat. Here we show for the first time ...that morphine failed to produce a place preference in rats with nerve injury. Various studies provide arguments to support that the mesolimbic dopaminergic system, which projects from the ventral tegmental area (VTA) to the nucleus accumbens (N.Acc), is critical of the motivational effects of opioids. In the present study, there were no significant differences between sham‐operated and sciatic nerve‐ligated rats in the increases in guanosine‐5′‐o‐(3‐35Sthio)triphosphate (35SGTPγS) binding to membranes of the N.Acc stimulated by either DA, the D1 receptor agonist SKF81297, the D2 receptor agonist N‐propylnoraporphine or the D3 receptor agonist 7‐hydroxy‐2‐dipropylaminotetralin (7‐OH DPAT). In contrast, the increases in 35SGTPγS binding to membranes of the VTA induced by either morphine or a selective µ‐opioid receptor agonist d‐Ala2, NMePhe4, Gly(ol)5enkephalin were significantly attenuated in nerve‐ligated rats as compared with sham‐ operated rats. Furthermore, the enhancement of DA release in the N.Acc stimulated by morphine was significantly suppressed by sciatic nerve ligation. These findings suggest that attenuation of the morphine‐induced place preference under neuropathic pain may result from a decrease in the morphine‐induced DA release in the N.Acc with reduction in the µ‐opioid receptor‐mediated G‐protein activation in the VTA.
PDF
