CD147 Expression Is Associated with Tumor Proliferation in Bladder Cancer via GSDMD.

PURPOSE: CD147, also known as BSG, is a type I transmembrane glycoprotein that belonged to immunoglobulin superfamily. Mature CD147 is an N-linked glycosylated protein and exists on the transmembrane and as soluble forms in tumors. However, the function of CD147 in cell proliferation of bladder cancer (BC) remains to be elucidated. METHODS: The study included 159 patients with BC and 68 healthy controls. The expression of CD147 and gasdermin D (GSDMD) was analyzed by immunohistochemistry (IHC). Western blotting was performed to detect the expression of proteins in BC cells. The relationship between CD147 and GSDMD was analyzed by the IHC score. RESULTS: The expression of CD147 was significantly increased in BC when compared to healthy controls, and the level of CD147 was correlated with tumor proliferation characterized by Ki-67, which is a cell proliferation antigen. In addition, CD147 treatment of BC cells increased the expression of GSDMD, leading to increased Ki-67 expression, while CD147 blockade with peptide in BC significantly reduced GSDMD expression, resulting in reduced cell proliferation. Furthermore, overexpression of GSDMD markedly overcame the inhibitory effect of CD147 peptide on tumor proliferation. BC patients with overexpression of CD147 showed correlation with GSDMD and demonstrated significantly poorer prognosis and overall survival rate. CONCLUSION: These findings suggested that high expression of CD147 contributed to tumor proliferation in BC via GSDMD, which might in turn act as an unfavorable prognostic marker.

Stable polyphosphate accumulation by a pseudo-revertant of an Escherichia coli phoU mutant.

phoU mutants of bacteria are potentially useful for the removal of inorganic phosphate (Pi) from sewage because they can accumulate a large amounts of polyphosphate (polyP). However, the growth of phoU mutants is severely defective and is easily outgrown by revertant(s) that have lost the ability to accumulate polyP during growth in a nutrient-rich medium. We found that a pseudo-revertant, designated LAP[+], that appeared in a culture of an Escherichia coli phoU mutant that could accumulate polyP even after ten serial passages. Reduction in the expression of the Pi-specific transporter Pst in LAP[+] may contribute to relieving stresses such as excess Pi incorporation that could stimulate reversions. The discovery of a LAP[+] provides a clue to generate phoU mutants that accumulate polyP in a stable manner.

The Pst system of Streptococcus mutans is important for phosphate transport and adhesion to abiotic surfaces.

The Pst system is a high-affinity inorganic phosphate transporter found in many bacterial species. Streptococcus mutans, the etiological agent of tooth decay, carries a single copy of the pst operon composed of six cistrons (pstS, pstC1, pstC, pstB, smu.1134 and phoU). Here, we show that deletion of pstS, encoding the phosphate-binding protein, reduces phosphate uptake and impairs cell growth, which can be restored upon enrichment of the medium with high concentrations of inorganic phosphate. The relevance of Pst for growth was also demonstrated in the wild-type strain treated with an anti-PstS antibody. Nevertheless, a reduced ability to bind to saliva-coated surfaces was observed, along with the reduction of extracellular polysaccharide production, although no difference on pH acidification was observed between mutant and wild-type strains. Taken together, the present data indicate that the S. mutans Pst system participates in phosphate uptake, cell growth and expression of virulence-associated traits.

Proteomics-based approach for identification and purification of human phosphate binding apolipoprotein from amniotic fluid.

Human amniotic fluid is of both maternal and fetal origin; it protects the fetus and provides the environment for growth and development of the fetus. We used a proteomics-based approach for targeting and purifying human phosphate binding protein, a member of the DING family of proteins from amniotic fluid, using Blue Sepharose CL-6B, DEAE-Sephacel and gel filtration chromatography. The protein had earlier been reported to be serendipitously purified along with PON1 (paraoxonase 1). It was identified using electro-spray-ionization-time-of-flight mass spectrometry and was found to be human phosphate binding protein. Human phosphate binding proteins have been reported to play a role as phosphate scavengers and may have a protective function against phosphate-related disorders, such as atherosclerosis, diabetes and kidney stones.