Project description:Metastasis is an important factor affecting the prognosis and survival of bladder cancer (BLCA) patients. Our previous study found that the mevalonate pathway is associated with the migratory ability of BLCA cells, but the exact mechanism is unclear. Here, we found that BLCA patients with mevalonate pathway activation had a poorer prognosis. Inhibition of the mevalonate pathway (FDPS knockdown, simvastatin or zoledronic acid) significantly reduced the migratory ability of BLCA cells. Therefore, we tested the changes of key genes after knocking down the key enzymes of the mevalonate pathway, FDPS and SQLE1, and the transcription factor YY1 in bladder cancer cells using RNA sequencing.
Project description:Metastasis is an important factor affecting the prognosis and survival of bladder cancer (BLCA) patients. Our previous study found that the mevalonate pathway is associated with the migratory ability of bladder cancer cells, but the exact mechanism is unclear. Here, we found that BLCA patients with mevalonate pathway activation had a poorer prognosis. Inhibition of the mevalonate pathway (simvastatin or zoledronic acid) resulted in a significant decrease in the migratory ability of BLCA cells. Therefore, we used proteomics to detect simvastatin- or zoledronic acid-treated BLCA cells to explore the effect of the mevalonate pathway on key proteins in BLCA cells.
Project description:Simvastatin has been widely used for treatment of hypercholesterolemia due to its ability to inhibit HMG-CoA reductase, the rate limiting enzyme of de novo cholesterol synthesis via mevalonate pathway. Its inhibitory action causes also depletion of pathway intermediates, farnesyl pyrophosphate (FPP) and geranyl-geranyl pyrophosphate (GGPP), which are inevitable for proper targeting of small GTPases (e.g. Ras proteins) to their site of action. We profiled by array the gene expression of MIA PaCa-2 cells treated with simvastatin, FPP, GGPP and their combinations. The inhibitory effect of statins on GFP-K-Ras protein trafficking were partially prevented by addition of the mevalonate pathway intermediates. We conclude that the anticancer effect of simvastatin is to a large extent mediated through isoprenoid intermediates of the mevalonate pathway.
Project description:Isoprenoids are a class of ubiquitous organic molecules synthesized from the five-carbon starter unit isopentenyl pyrophosphate (IPP). Comprising more than 30,000 known natural products, isoprenoids serve various important biological functions in many organisms. In bacteria, undecaprenyl pyrophosphate is absolutely required for the formation of cell wall peptidoglycan and other cell surface structures, while ubiquinones and menaquinones, both containing an essential prenyl moiety, are key electron carriers in respiratory energy generation. There is scant knowledge on the nature and regulation of bacterial isoprenoid pathways. In order to explore the cellular responses to perturbations in the mevalonate pathway, responsible for producing the isoprenoid precursor IPP in many Gram-positive bacteria and eukaryotes, we constructed three strains of Staphylococcus aureus in which each of the mevalonate pathway genes is regulated by an IPTG inducible promoter. We used DNA microarrays to profile the transcriptional effects of downregulating the components of the mevalonate pathway in S. aureus and demonstrate that decreased expression of the mevalonate pathway leads to widespread downregulation of primary metabolism genes, an upregulation in virulence factors and cell wall biosynthetic determinants, and surprisingly little compensatory expression in other isoprenoid biosynthetic genes. We subsequently correlate these transcriptional changes with downstream metabolic consequences. We used microarrays to profile the transcriptional changes incurred when downregulating mvaS, mvaA, or mvaK in S. aureus. Keywords: stress response S. aureus mutants were generated in which mvaS, mvaA, or mvaK were placed under control of the IPTG-inducible Pspac promoter. These mutants, as well as wildtype RN4220 S. aureus, were grown with or without 1 mM IPTG, harvested in exponential phase, and their total RNA was extracted and hybridized to Affymetrix GeneChips. Experiments were done in triplicate.
Project description:We have discovered that loss of wild-type p53 correlates with elevated expression of mevalonate pathway genes in murine liver cancer and in human tumors. Mechanistically p53 blocks activation of SREBP-2, the master transcriptional regulator of this pathway, by transcriptionally inducing the ABCA1 cholesterol transporter gene, which inhibits SREBP-2 maturation. In mice the increase in mevalonate gene expression occurs in premalignant p53-null hepatocytes at a stage when p53 is needed to actively suppress tumorigenesis. Either RNAi mediated suppression of key genes in the mevalonate pathway or pharmacological inhibition of its rate-limiting enzyme restricts the development of mouse hepatocellular carcinomas driven by p53 loss. Conversely, like p53 loss, ablation of ABCA1 promotes tumorigenesis in a murine model and is associated with increased SREBP-2 maturation. Our findings thereby demonstrate that repression of the mevalonate pathway is a crucial component of p53-mediated tumor suppression and outline the mechanism by which this occurs.
Project description:Isoprenoids are a class of ubiquitous organic molecules synthesized from the five-carbon starter unit isopentenyl pyrophosphate (IPP). Comprising more than 30,000 known natural products, isoprenoids serve various important biological functions in many organisms. In bacteria, undecaprenyl pyrophosphate is absolutely required for the formation of cell wall peptidoglycan and other cell surface structures, while ubiquinones and menaquinones, both containing an essential prenyl moiety, are key electron carriers in respiratory energy generation. There is scant knowledge on the nature and regulation of bacterial isoprenoid pathways. In order to explore the cellular responses to perturbations in the mevalonate pathway, responsible for producing the isoprenoid precursor IPP in many Gram-positive bacteria and eukaryotes, we constructed three strains of Staphylococcus aureus in which each of the mevalonate pathway genes is regulated by an IPTG inducible promoter. We used DNA microarrays to profile the transcriptional effects of downregulating the components of the mevalonate pathway in S. aureus and demonstrate that decreased expression of the mevalonate pathway leads to widespread downregulation of primary metabolism genes, an upregulation in virulence factors and cell wall biosynthetic determinants, and surprisingly little compensatory expression in other isoprenoid biosynthetic genes. We subsequently correlate these transcriptional changes with downstream metabolic consequences. We used microarrays to profile the transcriptional changes incurred when downregulating mvaS, mvaA, or mvaK in S. aureus. Keywords: stress response
Project description:The crosstalk between tumor cells and LECs triggers the LN metastasis in bladder cancer (BCa), but the underlying mechanisms are not completely understood. Previously, we identified that BCa-secreted extracellular vesicles (EVs)-packaged lncRNAs mediated the communication with LECs and promoted LN metastasis. To evaluate whether EV-packaged lncRNAs triggered the LN metastasis of BCa, next-generation sequencing (NGS) to the global expression profiles of lncRNAs was utilized in the urinary EVs (urinary-EV) of five MIBC patients and five healthy volunteers.
Project description:Bladder cancer is a highly metastatic tumor and one of the most common malignant tumors originating in the urinary system. Although the application of immune checkpoint, including programmed cell death-1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), achieved definite efficacy, the effect of immunotherapy for bladder cancer is still not very satisfactory. Therefore, it is very urgent to develop new targets to expand the options of immunotherapies. In this study, we utilized single cell sequencing to explore the cell composition and detected a subset of Treg cells with high expression of T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) and interleukin (IL)-32 molecules. Certainly, anti-tumor immune response was suppressed by this subset of Treg cells and IL-32 promoted the bladder cancer metastasis. Nevertheless, targeting TIGIT not only could reverse immunosuppression through restoring anti-tumor immune response mediated by T cells but suppressed the secretion of IL-32 and inhibited the metastasis of bladder cancer cells. Thus, our study provided a novel insight into the immunosuppression in bladder cancer and developed the TIGIT as the novel target for immunotherapy of bladder cancer. Furthermore, we also illustrated mechanism of the dual effect of targeting TIGIT in bladder cancer and revealed the metastasis-promoting effect of IL-32 in bladder cancer. Taken together, the discovery raises the possibility of TIGIT targets against bladder cancer from the bench to the bedside.
Project description:Mitochondrial dysfunction induces a strong adaptive retrograde signaling response, however many of the down-stream effectors remain to be discovered. Here, we studied the shared transcriptional responses to three different mitochondrial respiratory chain inhibitors in human primary skin fibroblasts using QuantSeq 3’RNA-sequencing. We found that mevalonate pathway genes were concurrently downregulated irrespective of the respiratory chain complex affected. Targeted metabolomics demonstrated that impaired mitochondrial respiration at any of the three affected complexes also had functional consequences on the mevalonate pathway, reducing cholesterol precursor metabolites. A deeper study of complex I inhibition showed a reduced activity of ER-bound sterol sensing enzymes through impaired processing of the transcription factor SREBP2 and accelerated degradation of the ER cholesterol sensors SQLE and HMGCR. These adaptations of mevalonate pathway activity neither affected total intracellular cholesterol levels nor the cellular free (non-esterified) cholesterol pool. Measurement of intracellular cholesterol using the fluorescent cholesterol binding dye filipin revealed that complex I inhibition elevated cholesterol on intracellular compartments. Our study shows that mitochondrial respiratory chain dysfunction elevates intracellular free cholesterol levels and therefore attenuates the expression of mevalonate pathway enzymes, which lowers endogenous cholesterol biosynthesis, disrupting the metabolic output of the mevalonate pathway. Intracellular disturbances in cholesterol homeostasis may alter systemic cholesterol management in diseases associated with declining mitochondrial function.