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Rcd1, initially identified as a factor essential for the commitment to nitrogen starvation-invoked differentiation in fission yeast, is one of the most conserved proteins found across eukaryotes, and its mammalian homolog is expressed in a variety of differentiating tissues. Here we show that mammalian Rcd1 is a novel transcriptional cofactor and is critically involved in the commitment step in the retinoic acid-induced differentiation of F9 mouse teratocarcinoma cells, at least in part, via forming complexes with retinoic acid receptor and activation transcription factor-2 (ATF-2). In addition, antisense oligonucteotide treatment of embryonic mouse lung explants suggests that Rcd1 also plays a role in retinoic acid-controlled lung development. [ABSTRACT FROM AUTHOR]

Background Previously, we reported that Sema3A, one of the secreted repulsive axon guidance molecules, CRMP (collapsin response mediator protein)-2, a putative intracellular signalling molecule for Sema3A and Sema3A receptor neuropilin-1 are expressed in the developing lung. Sema3A inhibits branching morphogenesis of embryonic lung in organ culture. Results We examined the gene expression of Sema3A, Sema3C, Sema3F and their receptors, NP-1, NP-2 and plexin-A1 by in situ hybridization. Transcripts of all six genes were detected in mouse lung from embryonic day E11.5 to E17.5, and displayed highly specific spatiotemporal distributions. The distribution of the receptor genes was detected in patterns which were consistent with known receptor usage of the semaphorins. In contrast to Sema3A, we found that the other class 3 semaphorins, Sema3C and Sema3F, stimulated branching morphogenesis. This stimulatory effect of Sema3C or Sema3F was accompanied by a moderate increase in the incorporation of bromodeoxyuridine (BrdU) into DNA in the terminal epithelial cells. Conclusion The coordinated expression patterns of different semaphorins and their receptors, together with the specific activities affecting branching morphogenesis, suggest that the semaphorins act as both positive and negative regulators of branching morphogenesis in the developing lung. [ABSTRACT FROM AUTHOR]

Tumor‐initiating cells are major drivers of chemoresistance and attractive targets for cancer therapy, however, their identity in human pancreatic ductal adenocarcinoma (PDAC) and the key molecules underlying their traits remain poorly understood. Here, we show that a cellular subpopulation with partial epithelial‐mesenchymal transition (EMT)‐like signature marked by high expression of receptor tyrosine kinase‐like orphan receptor 1 (ROR1) is the origin of heterogeneous tumor cells in PDAC. We demonstrate that ROR1 depletion suppresses tumor growth, recurrence after chemotherapy, and metastasis. Mechanistically, ROR1 induces the expression of Aurora kinase B (AURKB) by activating E2F through c‐Myc to enhance PDAC proliferation. Furthermore, epigenomic analyses reveal that ROR1 is transcriptionally dependent on YAP/BRD4 binding at the enhancer region, and targeting this pathway reduces ROR1 expression and prevents PDAC growth. Collectively, our findings reveal a critical role for ROR1high cells as tumor‐initiating cells and the functional importance of ROR1 in PDAC progression, thereby highlighting its therapeutic targetability. Synopsis: Cancer cell diversity and contribution of tumor‐initiating cells to pancreatic ductal adenocarcinoma (PDAC) progression remain poorly defined. In this work, single‐cell RNA sequencing and functional analyses uncovered targetable tumor‐initiating cells in PDAC. Heterogeneous tumor cells in PDAC arise from a subpopulation with partial EMT signature characterized by high expression of ROR1.Intratumoral ROR1high cells are tumor‐initiating cells with increased tumorigenic capacity.ROR1 functionally promotes PDAC tumor growth, relapse after chemotherapy, and metastasis.ROR1 induces the expression of AURKB via activation of AKT/c‐Myc/E2F signaling, thereby enhancing PDAC proliferation.ROR1 transcription is dependent on the YAP/BRD4 axis. [ABSTRACT FROM AUTHOR]

Introduction: The genomic characteristics of hepatocellular carcinoma (HCC) after a sustained virological response (SVR) and its differences according to whether an SVR was achieved by treatment with direct‐acting antivirals (DAA) or interferon (IFN) are still not fully understood. Methods: Sixty‐nine surgically resected HCCs from patients with hepatitis C virus infection were analyzed by gene expression profiling and whole‐exome sequencing. Results: Among the 69 HCC patients, 34 HCCs in which an SVR was not achieved at the time of surgery were classified as HCV‐positive, and 35 HCCs in which an SVR was achieved at the time of surgery were classified as HCV‐SVR. According to the HCV treatment, 35 HCV‐SVR HCCs were classified into two groups: eight tumors with DAA (HCV‐SVR‐DAA) and 24 tumors with interferon (HCV‐SVR‐IFN). The frequency of samples with ARID2 mutations was significantly lower in HCV‐SVR than in HCV‐positive tumors (p = 0.048). In contrast, the frequency of samples with PREX2 mutations was significantly higher in HCV‐SVR samples than in HCV‐positive samples (p = 0.048). Among the patients with HCV‐SVR, the frequency of samples with TP53 mutations was significantly higher in HCV‐SVR‐DAA tumors than in HCV‐SVR‐IFN tumors (p = 0.030). TP53 inactivation scores in HCV‐SVR‐DAA tumors were found to be significantly enhanced in comparison to HCV‐SVR‐IFN tumors (p = 0.022). In addition, chromosomal instability and PI3K/AKT/mTOR pathway signatures were enhanced in HCV‐SVR‐DAA tumors. HCV‐SVR‐DAA was significantly associated with portal vein invasion (p = 0.003) in comparison to HCV‐SVR‐IFN. Conclusion: Our dataset potentially serves as a fundamental resource for the genomic characteristics of HCV‐SVR‐DAA tumors. Our comprehensive genetic profiling by WES revealed significant differences in the mutation rate of several driver genes between HCV‐positive tumors and HCV‐SVR tumors. Furthermore, it was revealed that the frequency of samples with mutations in TP53 was significantly higher in HCV‐SVR‐DAA tumors than in HCV‐SVR‐IFN tumors. [ABSTRACT FROM AUTHOR]

To elucidate interactions between the glucose transport system and hepatic glucose production in the tumour-bearing state, glycogen storage, expression of glucose transporter isoform 2 (Glut 2) and activities of glucose-6-phosphatase (G-6-Pase) and hexokinase were histochemically examined in hepatocytes of tumour-bearing rats. Five male F344 rats, subcutaneously inoculated with methylcholanthrene(MCA)-induced sarcoma cells were compared with five pair-fed animals and four ad libitum fed controls. Glycogen storage was markedly decreased in liver cells of tumour-bearing rats compared to in those of control animals. Glut 2 immunoreactivity was uniformly seen in the cellular membrane of hepatocytes from control animals. In rats bearing sarcoma, the staining intensity was significantly decreased, suggesting that Glut 2 with its bi-directional transport capacity was down-regulated in the tumour-bearing state. Positive staining for hexokinase activity was located in the perivenous area in livers from control animals and was more diffusely located and more intense in livers from tumour-bearing animals. G-6-Pase activity, limited to the peripheral area in livers from controls, extended to the intermediate area and had stronger reactivity in livers from tumour-bearing animals. In the tumour-bearing cachectic condition, glucose may be partially consumed by a futile cycle, hepatic metabolic zonation was disturbed, and the release of glucose from the liver may not be mediated by a facilitative glucose transporter-2. [ABSTRACT FROM AUTHOR]

Background Small cell lung carcinoma ( SCLC) is characterized by a high rate of relapse and failure of chemotherapy because of the emergence of drug resistant cells. Notch signaling controls carcinogenesis in several human malignancies and could be involved in the resistance of cells to several chemotherapeutic agents. Herein, we analyzed the role of Notch1 signaling in the resistance of human SCLC cells to doxorubicin. Methods Small interfering ribonucleic acid technology was used to knock down ( KD) Notch1 in H69 AR and SBC-3 SCLC cells. We detected the effect of inhibiting Notch1 on the expression of drug resistant related molecules: multidrug resistance-associated protein ( MRP-1) and anti-apoptotic factor B-cell lymphoma-2, as well as to cell adhesion molecule E-cadherin, which contributes to the adhesion of SCLC cells to the extracellular matrix and confers chemoresistance in a process known as cell adhesion-mediated drug resistance ( CAM-DR). We also observed the effect of KD Notch1 on cell survival under high concentrations of doxorubicin treated media. Results H69 AR and SBC-3 cells expressed Notch1 protein and grew as adherent aggregates, which confer resistance to high concentrations of doxorubicin. On inhibiting Notch1, we observed activation of the apoptotic pathway in cells, possibly resulting from the loss of CAM-DR and, thus, SBC-3 cells showed a loss of chemoresistant ability. However, in H69 AR cells with KD Notch1, the expression of MRP-1 was increased and, thus, sustained the chemoresistant ability of cells. Conclusion The Notch1 signaling pathway is involved in mediating the drug resistance phenotype of SCLC cells. [ABSTRACT FROM AUTHOR]

Brefeldin A induces a rapid redistribution of cost proteins associated with clathrin-coated vesicles that bud from the tans-Golgi network but not of those associated with vesicles derived from the plasma membrane. Its effect on glucose transport and the subcellular distribution of the glucose transporter CLUT4 were therefore investigated in the absence or in the presence of insulin in order to characterize the mechanism of insulin-induced GLUT4 recycling. Exposure of rat adipose cells to befeldin A in the absence of insulin resulted in a slight increase both in 3-O-methyl-D-glocose transport and in the amount of GLUT4 in the plasma membrane as determined by immunoblot analysis. In contrast, it had no effect on the insulin-induced increase in 3-O-methyl-glucose transport and plasma-membrane-associated GLUT4. Immunohistochemical analysis revealed clathrin immunoreactivity in the juxtanuclear region and in the cell periphery, and the staining in the perinuclear region decreased after exposure of cells to 35 μM brefeldin A. However, it had no effect on the basal pattern of GLUT4 staining or on the insulin-induced redistribution of GLUT4 staining to the cell periphery. These results suggest that basal recycling of GLUT4 responsible for maintaining the intracellular location of the transporter may include a membrane budding step sensitive to brefeldin A, possibly associated with clathrin-coated vesicles, but that the insulin-stimulated GLUT4 recycling pathway is mediated predominatly by a brefeldin A-insensitive mechanism. [ABSTRACT FROM AUTHOR]