Reduced RCE1 expression predicts poor prognosis of colorectal carcinoma

LNP-miR-155 cy5 Inhibitor Regulates the Copper Transporter via the β-Catenin/TCF4/SLC31A1 Signal for Colorectal Cancer Therapy

Lipid nanoparticle (LNP) delivery systems are widely used in the delivery of small-molecule drugs and nucleic acids. In this study, we prepared LNP-miR-155 by lipid nanomaterial technology and investigated the effects of LNP-miR-155 on β-catenin/transcription factor 4 (TCF4)/solute carrier family 31 member 1/copper transporter 1 (SLC31A1/CTR1) signaling and copper transport in colorectal cancer. For this, we used an LNP-miR-155 cy5 inhibitor and LNP-miR-155 cy5 mimics for the transfection of HT-29/SW480 cells. The transfection efficiency and uptake efficiency were detected by immunofluorescence. Relevant cell assays confirmed that the LNP-miR-155 cy5 inhibitor mediates the regulation of copper transport through the β-catenin/TCF4/SLC31A1 axis. The LNP-miR-155 cy5 inhibitor reduced cell proliferation, migration, and colony formation and promoted cell apoptosis. We also confirmed that miR-155 downregulates HMG box-containing protein 1 (HBP1) and adenomatous polyposis coli (APC) in cells and activates the function of β-catenin/TCF4 signaling. In addition, we found that the copper transporter, SLC31A1, is highly expressed in colorectal cancer cells. Furthermore, we also found that the complex β-catenin/TCF4 promotes the transcription of SLC31A1 by binding to its promoter region, which sustains the transport of copper from the extracellular region to the intracellular region and increases the activities of Cu2+-ATPase and superoxide dismutase (SOD). In summary, the LNP-miR-155 cy5 inhibitor regulates β-catenin/TCF4 by downregulating SLC31A1-mediated copper transport and intracellular copper homeostasis.

Comparative analysis of the occupancy of Histone H3 Lysine 4 methylation in the cells treated with TGFβ and Interferonγ

In this current study, we have compared our H3K4me3 Chip-Sequencing data in PC3 cells in response to 6h and 24h TGFβ stimulation with the IFNγ stimulated/unstimulated HeLa S3 cells Since both TGFβ and IFNγ play an essential role in tumorigenesis both as a tumor promoter and tumor suppressor and known to antagonize each other's signalling, it would be of utmost importance to find out the regions undergoing histone modification changes in response to TGFβ and IFNγ and compare them to explore the genes common to both as well as the specific for each ligand. Our study has compared the genes showing H3K4me3 occupancy in response to both TGFβ and IFNγ. Several genes were found to be shared between the TGFβ and IFNγ. DAVID Functional enrichment analysis in the TGFβ and IFNγ dataset revealed association of genes with different biological processes such as miRNA-mediated gene silencing, positive regulation of ERK cascade, hypoxia-induced apoptosis repression, translational regulation and molecular functions such as TGFβR activity, GPCR activity, TGFβ binding activity. Further analysis of these genes can reveal fascinating insights into epigenetic regulation by growth factor stimulation.

RCE1 deficiency enhances invasion via the promotion of epithelial-mesenchymal transition and predicts poor prognosis in hepatocellular carcinoma

Ras converting CAAX endopeptidase 1 (RCE1) is an integral membrane protease involved in cell proliferation, differentiation, and carcinogenesis. RCE1 plays opposite roles in different tumor types; however, the actual biological function of RCE1 in hepatocellular carcinoma (HCC) is unknown. Here, we aim to investigate the prognostic value and molecular function of RCE1 in HCC. We performed immunohistochemistry in 20 normal human liver, 216 HCC, and 216 adjacent non-tumorous tissues and analyzed the expression change and clinical value of RCE1. Additionally, in vitro and in vivo studies were performed to investigate the role of RCE1 in regulating HCC proliferation, invasion, and metastasis. We found decreased RCE1 expression in HCC tissues. Moreover, the RCE1 expression level was negatively correlated with pathological parameters characteristic of early recurrence (P < 0.044) and the serum alpha-fetoprotein (AFP) level (P < 0.018). Survival analysis indicated that reduced RCE1 expression was a predictor of poor outcomes in patients with HCC. Functional studies showed that the knockdown of RCE1 promoted proliferation, migration, and invasion of HCC cells, while RCE1 overexpression suppressed these effects. In vivo studies further confirmed that the stable knockdown of RCE1 resulted in more rapid tumor growth and an increased number of lung metastatic nodules. Mechanistically, we found that RCE1 deficiency induced epithelial-mesenchymal transition (EMT) via activation of the P38 signaling pathway. Collectively, these results indicate that RCE1 deficiency enhances invasion via promoting epithelial-mesenchymal transition. The downregulation of RCE1 in HCC tissues predicts an unsatisfactory prognosis for patients with HCC.

Rce1 suppresses invasion and metastasis of hepatocellular carcinoma via epithelial-mesenchymal transition induced by the TGF-β1/H-Ras signaling pathway

Ras converting enzyme 1 (Rce1) plays an important role in invasion and metastasis of malignancy. However, the mechanism has not yet been fully explored in hepatocellular carcinoma (HCC). Primarily, we investigated the expression of Rce1 and H-Ras influence on patient prognosis through the clinical data. Further, we analyzed the regulatory effects of Rce1/H-Ras signal pathway on the epithelial-mesenchymal transition (EMT) in vitro and in vivo. Finally, we screened out the protein which bonds with Rce1 by CO-IP experiment to discuss the mechanism of Rce1 in EMT of HCC. This research revealed a significantly decreased expression of Rce1 in HCC compared with noncancerous tissues (p < .05). In contrast, H-Ras expression was increased in the tumor. The expression of them was a close association with the differentiation and tumor-node-metastasis (TNM) stage of the tumor (p < .001; p = .035, respectively) and Rce1 was an independent prognostic indicator (95%Cl: 0.193-0.821; p = .013). Through targeted regulation of Rce1 by cDNA or small interfering RNA, results show that the lower expression of Rce1 facilitated EMT and promoted the invasion and metastasis of HCC (p < .05). Furthermore, the CO-IP experiment unfolded that Rce1 could bond with farnesyltransferase-β (FNTB) which mediated the expression of H-Ras. Conclusions: Rce1 inhibits EMT via target regulation H-Ras and suppress the early invasion and metastasis of HCC. It may be a potential therapeutic target and prognostic indicator for HCC.

Rce1: mechanism and inhibition

Ras converting enzyme 1 (Rce1) is an integral membrane endoprotease localized to the endoplasmic reticulum that mediates the cleavage of the carboxyl-terminal three amino acids from CaaX proteins, whose members play important roles in cell signaling processes. Examples include the Ras family of small GTPases, the γ-subunit of heterotrimeric GTPases, nuclear lamins, and protein kinases and phosphatases. CaaX proteins, especially Ras, have been implicated in cancer, and understanding the post-translational modifications of CaaX proteins would provide insight into their biological function and regulation. Many proteolytic mechanisms have been proposed for Rce1, but sequence alignment, mutational studies, topology, and recent crystallographic data point to a novel mechanism involving a glutamate-activated water and an oxyanion hole. Studies using in vivo and in vitro reporters of Rce1 activity have revealed that the enzyme cleaves only prenylated substrates and the identity of the a₂ amino residue in the Ca₁a₂X sequence is most critical for recognition, preferring Ile, Leu, or Val. Substrate mimetics can be somewhat effective inhibitors of Rce1 in vitro. Small-molecule inhibitor discovery is currently limited by the lack of structural information on a eukaryotic enzyme, but a set of 8-hydroxyquinoline derivatives has demonstrated an ability to mislocalize all three mammalian Ras isoforms, giving optimism that potent, selective inhibitors might be developed. Much remains to be discovered regarding cleavage specificity, the impact of chemical inhibition, and the potential of Rce1 as a therapeutic target, not only for cancer, but also for other diseases.