ABSTRACT
BACKGROUND: Intestinal microbial dysbiosis is involved in liver disease pathogenesis. However, its role in primary liver cancer (PLC), particularly in hepatocarcinogenesis remains unclear. The present study aimed to study the changes in intestinal flora at various stages of PLC and clarify the relationship between intestinal microbes and PLC. METHODS: Twenty-four patients with PLC (PLC group), 24 patients with liver cirrhosis (LC group), and 23 healthy control individuals (HC group) were enrolled from October 2016 to October 2017. Stool specimens of the participants were collected and the genomic DNA of fecal bacteria was isolated. High-throughput pyrosequencing of 16S rDNA was used to identify differences in gut bacterial diversity among HC, LC, and PLC groups. We also analyzed the relationship between clinical factors and intestinal microorganisms in LC and PLC groups. RESULTS: Diversity of Firmicutes tended to decrease from the HC to LC and PLC groups at the phylum level. Among species, Enterobacter ludwigii displayed an increasing trend in the PLC group, wherein the relative abundance of Enterobacter ludwigii in the PLC group was 100 times greater than that in the HC and LC groups. The ratio of Firmicutes/Bacteroidetes was significantly decreased with the disease progression. In addition, the linear discriminant analysis effect size method indicated that Clostridia were predominant in the gut microbiota of the HC group, whereas Enterococcaceae, Lactobacillales, Bacilli and Gammaproteobacteria may be used as diagnostic markers of PLC. Redundancy analysis showed a correlation between intestinal microbial diversity and clinical factors AST, ALT, and AFP. Veillonella showed a significant positive correlation with AFP in the PLC group, whereas Subdoligranulum showed a negative correlation with AFP. CONCLUSIONS: This study indicates that dysbiosis of the gut microbiota might be involved in PLC development and progression.
Subject(s)
Dysbiosis/pathology , Gastrointestinal Microbiome , Intestinal Mucosa/microbiology , Liver Neoplasms/microbiology , Liver Neoplasms/pathology , Aged , Case-Control Studies , Disease Progression , Female , Humans , Liver Cirrhosis/microbiology , Liver Cirrhosis/pathology , Male , Microbiota , Middle Aged , Reference Values , Risk AssessmentABSTRACT
Our previous finding of RTVP1 (GLIPR1) as a p53 target gene with tumor suppressor functions prompted us to initiate a genome-wide sequence homology search for RTVP1/GLIPR1-like (GLIPR1L) genes. In this study we report the identification and characterization of a novel p53 target gene cluster that includes human RTVP1 (hRTVP-1) together with two GLIPR1L genes (GLIPR1L1 and GLIPR1L2) on human chromosome 12q21 and mouse Rtvp1 (mRTVP-1 or Glipr1) together with three Glipr1-like (Glipr1l) genes on mouse chromosome 10D1. GLIPR1L1 has two and GLIPR1L2 has five differentially spliced isoforms. Protein homology search revealed that hRTVP-1 gene cluster members share a high degree of identity and homology. GLIPR1L1 is testis-specific, whereas GLIPR1L2 is expressed in different types of tissues, including prostate and bladder. Like hRTVP-1, GLIPR1L1 and GLIPR1L2 are p53 target genes. The similarities of these novel p53 target gene cluster members in protein structure and their association with p53 suggest that these genes may have similar biological functions.
Subject(s)
Multigene Family , Neoplasm Proteins/genetics , Nerve Tissue Proteins/genetics , Tumor Suppressor Protein p53/metabolism , Amino Acid Sequence , Animals , Base Sequence , Chromosome Mapping , Chromosomes, Human, Pair 12 , Humans , Male , Membrane Proteins , Mice , Models, Genetic , Molecular Sequence Data , Neoplasm Proteins/metabolism , Nerve Tissue Proteins/metabolism , Sequence Alignment , Sequence Homology , Species Specificity , Testis/cytology , Testis/metabolismABSTRACT
Previously it has been reported that caveolin-1 (cav-1) has antiapoptotic activities in prostate cancer cells and functions downstream of androgenic stimulation. In this study, we demonstrate that cav-1 overexpression significantly reduced thapsigargin (Tg)-stimulated apoptosis. Examination of the phosphatidylinositol 3-kinase (PI3-K)/Akt signaling cascade revealed higher activities of PDK1 and Akt but not PI3-K in cav-1-stimulated cells compared to control cells. We subsequently found that cav-1 interacts with and inhibits serine/threonine protein phosphatases PP1 and PP2A through scaffolding domain binding site interactions. Deletion of the cav-1 scaffolding domain significantly reduces phosphorylated Akt and cell viability compared with wild-type cav-1. Analysis of potential substrates for PP1 and PP2A revealed that cav-1-mediated inhibition of PP1 and PP2A leads to increased PDK1, Akt, and ERK1/2 activities. We demonstrate that increased Akt activities are largely responsible for cav-1-mediated cell survival using dominant-negative Akt mutants and specific inhibitors to MEK1/MEK and show that cav-1 increases the half-life of phosphorylated PDK1 and Akt after inhibition of PI3-K by LY294002. We further demonstrate that cav-1-stimulated Akt activities lead to increased phosphorylation of multiple Akt substrates, including GSK3, FKHR, and MDM2. In addition, overexpression of cav-1 significantly increases translocation of phosphorylated androgen receptor to nucleus. Our studies therefore reveal a novel mechanism of Akt activation in prostate cancer and potentially other malignancies.
