Rifaximin, a non-absorbable antibiotic, inhibits the release of pro-angiogenic mediators in colon cancer cells through a pregnane X receptor-dependent pathway.
Activation of intestinal human pregnane X receptor (PXR) has recently been proposed as a promising strategy for the chemoprevention of inflammation-induced colon cancer. The present study was aimed at evaluating the effect of rifaximin, a non-absorbable antibiotic, in inhibiting angiogenesis in a model of human colorectal epithelium and investigating the role of PXR in its mechanism of action. Caco-2 cells were treated with rifaximin (0.1, 1.0 and 10.0 µM) in the presence or absence of ketoconazole (10 µM) and assessed for cell proliferation, migration and expression of proliferating cell nuclear antigen (PCNA). The release of vascular endothelial growth factor (VEGF) and nitric oxide (NO), expression of Akt, mechanistic target of rapamycin (mTOR), p38 mitogen activated protein kinases (MAPK), nuclear factor κB (NF-κB) and metalloproteinase-2 and -9 (MMP-2 and -9) were also evaluated. Treatment with rifaximin 0.1, 1.0 and 10.0 µM caused significant and concentration-dependent reduction of cell proliferation, cell migration and PCNA expression in the Caco-2 cells vs. untreated cells. Treatment downregulated VEGF secretion, NO release, VEGFR-2 expression, MMP-2 and MMP-9 expression vs. untreated cells. Rifaximin treatment also resulted in a concentration-dependent decrease in the phosphorylation of Akt, mTOR, p38MAPK and inhibition of hypoxia-inducible factor 1-α (HIF-1α), p70S6K and NF-κB. Ketoconazole (PXR antagonist) treatment inhibited these effects. These findings demonstrated that rifaximin causes PXR-mediated inhibition of angiogenic factors in Caco-2 cell line and may be a promising anticancer tool.
Department of Physiology and Pharmacology, 'Vittorio Erspamer', La Sapienza University of Rome, I-00185 Rome, Italy.
Giuseppe
G
Esposito
Department of Physiology and Pharmacology, 'Vittorio Erspamer', La Sapienza University of Rome, I-00185 Rome, Italy.
Stefano
S
Gigli
Department of Physiology and Pharmacology, 'Vittorio Erspamer', La Sapienza University of Rome, I-00185 Rome, Italy.
Luisa
L
Seguella
Department of Physiology and Pharmacology, 'Vittorio Erspamer', La Sapienza University of Rome, I-00185 Rome, Italy.
Nicola
N
Nobile
Department of Clinical Medicine and Surgery, 'Federico II' University of Naples, I-80131 Naples, Italy.
Alessandra
A
D'Alessandro
Department of Clinical Medicine and Surgery, 'Federico II' University of Naples, I-80131 Naples, Italy.
Marcella
M
Pesce
Department of Physiology and Pharmacology, 'Vittorio Erspamer', La Sapienza University of Rome, I-00185 Rome, Italy.
Elena
E
Capoccia
Department of Physiology and Pharmacology, 'Vittorio Erspamer', La Sapienza University of Rome, I-00185 Rome, Italy.
Luca
L
Steardo
Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, 3000 Leuven, Belgium.
Carla
C
Cirillo
Department of Clinical Medicine and Surgery, 'Federico II' University of Naples, I-80131 Naples, Italy.
Rosario
R
Cuomo
Department of Clinical Medicine and Surgery, 'Federico II' University of Naples, I-80131 Naples, Italy.
Giovanni
G
Sarnelli
D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D018938:Caco-2 Cells; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000209:etiology / Q000235:genetics / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007249:Inflammation / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D007654:Ketoconazole / Q000008:administration & dosage; D009363:Neoplasm Proteins / Q000096:biosynthesis; D009389:Neovascularization, Pathologic / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D000077297:Pregnane X Receptor; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis; D011987:Receptors, Steroid / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D012294:Rifamycins / Q000008:administration & dosage*; D000078262:Rifaximin; D015398:Signal Transduction / Q000187:drug effects
D000900:Anti-Bacterial Agents; D009363:Neoplasm Proteins; D000077297:Pregnane X Receptor; D018809:Proliferating Cell Nuclear Antigen; D011987:Receptors, Steroid; D012294:Rifamycins; D000078262:Rifaximin; D007654:Ketoconazole