Prostaglandin E2 promotes hepatocellular carcinoma cell proliferation through EP2 prostanoid receptor / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of prostaglandin E2 (PGE(2)) on the proliferation of cultured hepatocellular carcinoma cells and explore which subtypes of EP prostanoid receptor mediate the action.</p><p><b>METHODS</b>RT-PCR was used to determine COX-2 and EP receptor mRNA expression levels in human hepatocellular carcinoma cell line Hep3B and human normal hepatocyte line QSG7701. Cell counting kit-8 (CCK-8) assay was employed to investigate the effect of PGE(2), selective EP2 receptor agonist butaprost and EP3/EP4 receptor agonist PGE1 alcohol on the proliferation of the cells.</p><p><b>RESULTS</b>COX-2 mRNA was highly expressed in Hep3B cells but scarcely in QSG7701 cells. Hep3B cells expressed the mRNAs for all the EP receptor subtypes, but EP2 and EP4 receptors were much more strongly expressed than EP1 and EP3 receptors. PGE(2) significantly promoted Hep3B cell proliferation in a time- and dose-dependent manner, and 10 µmol/L PGE(2) increased the cell proliferation by 22.57% (P<0.001) after a 48-h incubation; treatment with 0.1, 1.0, and 10 µmol/L PGE(2) for 72 h resulted in significantly increased cell proliferation by 12.13% (P<0.01), 17.58% (P<0.01) and 33.07% (P<0.001), respectively. EP2 receptor agonist butaprost (20 µmol/L) increased Hep3B cell proliferation by 21.96% (P<0.001), but the EP3/EP4 receptor agonist PGE(1) alcohol (2-20 µmol/L) exhibited no significant mitogenic effect in Hep3B cells, and 200 µmol/L PGE(1) alcohol decreased the cell viability.</p><p><b>CONCLUSION</b>Selective activation of EP2 receptor promotes Hep3B cell proliferation, indicating the predominant role of EP2 receptor in mediating the mitogenic effect of PGE2.</p>

Immunomodulatory effects of Fomes fomentarius polysaccharides: an experimental study in mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the immunomodulatory effects of Fomes fomentarius polysaccharides (FFP) in mice.</p><p><b>METHODS</b>MTT assay was employed to evaluate the in vitro metabolic activity of the mouse splenocytes treated with FFP at different concentrations, and the secretion of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (INF-gamma) and interleukin 2 (IL-2) from the cells were measured by enzyme-linked immunosorbent assay. The changes in the phagocytotic activity of mouse macrophage in response to FFP treatment were evaluated by phagocytosis percentage of chicken red blood cells (CRBCs). The effect of FFP on the humoral immunity was assessed in mice immunized with sheep red blood cells (SRBCs) by measuring the serum levels of specific antibody (hemolysin) against SRBCs.</p><p><b>RESULTS</b>FFP at the concentrations of 25, 50, and 100 microg/ml all significantly enhanced the metabolic activity of mouse splenocytes in vitro and increased the production of TNF-alpha, IFN-gamma and IL-2. FFP treatment also markedly enhanced the metabolic activity of mouse peritoneal exudate cells and TNF-alpha production by the cells. At the doses of 25, 50, and 100 mg/kg, FFP significantly increased serum hemolysin level in mice immunized with SRBCs, and FFP at 50 and 100 mg/kg obviously increased the capacity of mouse peritoneal macrophages in vivo for CRBC phagocytosis.</p><p><b>CONCLUSION</b>FFP can promote the secretion of TNF-alpha, IFN-gamma and IL-2 by mouse immunocytes and enhance mouse humoral immune response and the phagocytotic activity of the macrophages.</p>

Effects of lipopolysaccharides of Bacterium prodigiosum on tumor growth and immunosuppression in mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effects of lipopolysaccharides of Bacterium prodigiosum (BP-LPS) in inhibiting tumor growth and improving immunosuppression in mice.</p><p><b>METHODS</b>In mice bearing S180 tumor and a mouse model of immunosuppression induced by cyclophosphamide (CTX), the tumor growth, indexes of the immune organs and peripheral white blood cell count were measured after intraperitoneal injection of BP-LPS.</p><p><b>RESULTS</b>Injections of BP-LPS (40 U/kg) for 8 consecutive days resulted in a significant inhibition of the tumor growth in mice bearing S180 tumor (P<0.01), with a dose-dependent increase of the spleen indexes but no obvious changes in the thymus indexes. Intraperitoneal injections of BP-LPS for 7 days inhibited the reduction of peripheral white blood cells and spleen indexes in immunosuppressive mice, but did not produce any significant changes in normal mice.</p><p><b>CONCLUSION</b>BP-LPS can inhibit the tumor growth in tumor-bearing mice and enhance the immune functions of immunosuppressive mice.</p>

Establishment of mouse model of humoral immune response using rabbit red blood cells as the antigen / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a mouse model of humoral immune response by immunization with rabbit red blood cells (RRBCs).</p><p><b>METHODS</b>The mice were immunized with RRBCs and the serum hemolysin level was measured by micro-hemolysis spectrophotometry.</p><p><b>RESULTS</b>The peak time needed for hemolysin production against RRBCs was 6 days after the immunization, and 20% RRBCs in a total volume of 0.2 ml was optimal for intraperitoneal injection. Hydrocortisone (25 mg/kg) and cyclophosphamide (20 mg/kg) inhibited hemolysin production. Mannatide (4 mg/kg) produced no significant effect on serum hemolysin level in normal mice, but significantly potentiated hemolysin production in immunosuppressed mice induced by cyclophosphamide (20 mg/kg).</p><p><b>CONCLUSION</b>Intraperitoneal RRBC injection is feasible for establishing mouse models of humoral immune response.</p>

Diclofenac suppresses hepatoma cell proliferation and promotes cyclooxygenase-2 mRNA expression / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of cyclooxygenase inhibitor diclofenac on the proliferation and cyclooxygenase-2 (COX-2) mRNA expression of cultured hepatocellular carcinoma cell lines HepG2, Hep3B and human hepatocellular cell line QSG-7701.</p><p><b>METHODS</b>After exposure to diclofenac at various concentrations (10-200 micromol/L) for 24, 48 and 72 h, the cell proliferation was analyzed by Cell Counting Kit-8 (CCK-8) assay and mRNA expression determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>Diclofenac exposure for 24, 48 and 72 h significantly inhibited HepG2 and Hep3B cell proliferation in a concentration-dependent manner, with inhibition rate of 40.47% and 54.49% after 48 h exposure to 50 micromol/L diclofenac and IC50 of 70.54 and 48.39 micromol/L, respectively. A much weaker antiproliferative effect on QSG-7701 cells was shown, with IC50 of 189.91 micromol/L after 48-hour exposure to diclofenac. RT-PCR detected COX-2 mRNA in HepG2 and Hep3B cells, but hardly in QSG-7701 cells. Treatment with diclofenac or 5-Fu resulted in elevated COX-2 mRNA expression both in HepG2 and Hep3B cells.</p><p><b>CONCLUSION</b>Diclofenac can specifically inhibit the proliferation of COX-2-expressing HepG2 and Hep3B cells, and induce up-regulation of COX-2 mRNA expression, which indicates the important role of COX-2 in the proliferation of hepatoma cells.</p>