Bacterial adherence to epithelial cells is a key virulence trait of pathogenic bacteria. The type 1 fimbriae and the P-fimbriae of uropathogenic Escherichia coli (UPEC) have both been described to be important for the establishment of urinary tract infections (UTI). To explore the interactions between the host and bacterium responsible for the different environments of UPEC invasion, we examined the effect of pH and osmolarity on UPEC strain J96 fimbrial expression, and subsequent J96-induced interleukin-8 (IL-8) expression in different uroepithelial cells. The J96 strain grown in high pH with low osmolarity condition was favorable for the expression of type 1 fimbriae; whereas J96 grown in low pH with high osmolarity condition was beneficial for P fimbriae expression. Type 1 fimbriated J96 specifically invaded bladder 5637 epithelial cells and induced IL-8 expression. On the contrary, P fimbriated J96 invaded renal 786-O epithelial cells and induced IL-8 expression effectively. Type 1 fimbriated J96-induced IL-8 induction involved the p38, as well as ERK, JNK pathways, which leads to AP-1-mediated gene expression. P fimbriated J96-induced augmentation of IL-8 expression mainly involved p38-mediated AP-1 and NF-κB transcriptional activation. These results indicate that different expression of fimbriae in J96 trigger differential IL-8 gene regulation pathways in different uroepithelial cells.

Some phytochemicals with the characteristics of cytotoxicity and/or antimetastasis have generated intense interest among the anticancer studies. In this study, a natural flavonoid baicalein was evaluated in bladder cancer in vitro and in vivo. Baicalein inhibits 5637 cell proliferation. It arrests cells in G1 phase at 100 μM and in S phase below 75 μM. The protein expression of cyclin B1 and cyclin D1 is reduced by baicalein. Baicalein-induced p-ERK plays a minor role in cyclin B1 reduction. Baicalein-inhibited p65NF-κB results in reduction of cell growth. Baicalein-induced pGSK(ser9) has a little effect in increasing cyclin B1/D1 expression instead. The translation inhibitor cycloheximide blocks baicalein-reduced cyclin B1, suggesting that the reduction is caused by protein synthesis inhibition. On the other hand, neither cycloheximide nor proteasome inhibitor MG132 completely blocks baicalein-reduced cyclin D1, suggesting that baicalein reduces cyclin D1 through protein synthesis inhibition and proteasomal degradation activation. In addition, baicalein also inhibits cell invasion by inhibiting MMP-2 and MMP-9 mRNA expression and activity. In mouse orthotopic bladder tumor model, baicalein slightly reduces tumor size but with some hepatic toxicity. In summary, these results demonstrate the anti-bladder-tumor properties of the natural compound baicalein which shows a slight anti-bladder-tumor effect in vivo.

Aim: To examine the antitumor effect of 4′-chloro-3,5-dihydroxystilbene, a resveratrol derivative, on lung adenocarcinoma A549 cells. Methods: The cytotoxic IC 50 was determined by direct cell counting. Flow cytometry, monodansylcadaverine (MDC) staining, transfection, Western blot and a proteasome activity assay were used to study the cellular mechanism of 4′-chloro-3,5-dihydroxystilbene. A xenograft nude mouse model was used to analyze the antitumor effect in vivo. Results: 4′-Chloro-3,5-dihydroxystilbene induced a rapid and persistent increase in the intracellular reactive oxygen species in the cells, but the cell death could not be inhibited by two antioxidant agents. The derivative caused sub-G 1 formation, a decrease in the mitochondria membrane potential and poly (ADP-ribose) polymerase degradation, and the caspase inhibitor Z-VAD-FMK could partially prevent cell death. It also induced a significant increase in intracellular acidic vacuoles, LC3-II formation and intracellular GFP-LC3 aggregation. An autophagic inhibitor partially reversed cell death. Additionally, 4′-chloro-3,5-dihydroxystilbene induced the accumulation of ubiquitinated conjugates and inhibited proteasome activity in cells. In an in vivo study, 4′-chloro-3,5-dihydroxystilbene retarded tumor growth in nude mice. Conclusion: These data suggest that the resveratrol derivative 4′-chloro-3,5-dihydroxystilbene could be developed as an anti-tumor compound.