Tumor necrosis factor-α induces expression and release of interleukin-6 by human urothelial cells

OBJECTIVE

We examined the effects of tumor necrosis factor-α (TNF-α) on expression and release of interleukin-6 (IL-6) by human urothelial cells (HUCs) and investigated whether the effects of TNF-α are mediated by mitogen-activated protein kinase (MAPK) pathways.

MATERIALS AND METHODS

HUCs were treated with TNF-α at 1-10 ng/ml for 2-24 h. Expression of IL-6 and TNF-α receptor 1 (TNFR1) mRNAs were examined by real-time PCR. The release of IL-6 into culture medium was determined by ELISA. The presence of TNFR1 protein and TNF-α-induced activation of MAPK pathways was examined by immunoblotting analysis. The effects of selective blockers of MAPK pathways on TNF-α-induced IL-6 expression and release were determined.

RESULTS

TNF-α increased IL-6 mRNA expression and stimulated release of IL-6 in a concentration- and time-dependent manner. The effects of TNF-α were mediated by TNFR1. TNF-α induced phosphorylation of ERK1/2 and JNK, and TNF-α-induced IL-6 expression and release were inhibited by selective ERK1/2 and JNK blockers.

CONCLUSIONS

These results demonstrate that TNF-α increases expression and release of IL-6 by HUCs and that the effects of TNF-α are mediated by TNFR1. Also, the ERK1/2 and JNK pathways are involved in TNF-α-induced expression and release of IL-6 in HUCs and may represent therapeutic targets in inflammatory urinary tract diseases.

N-(4-hydroxyphenyl)retinamide (4-HPR) decreases neoplastic properties of human prostate cells: an agent for prevention

The development of prostate cancer through a multistep process of carcinogenesis may have a long latent period of 20-30 years. It is possible that progression to a malignant state could be blocked or reversed during this time. This study focuses on the ability of the synthetic retinoid, N-(4-hydroxyphenyl)-retinamide (4-HPR), to reverse changes associated with malignant transformation and tumor progression, towards a normal phenotype. To examine the responsiveness of cells at different steps of prostate carcinogenesis, three immortalized, but non-tumorigenic (RWPE-1, WPE1-7 and WPE1-10), and one human prostate carcinoma cell line (DU-145), were used. The effects of 4-HPR on cell proliferation, expression of intermediate filament proteins cytokeratin 18 and vimentin, and tumor suppressor proteins p53 and pRb were examined by immunostaining and compared. Results show that 4-HPR caused inhibition of growth in all cell lines in a dose-dependent manner. 4-HPR induced an increase in staining for cytokeratin 18, a marker of differentiation for prostate epithelial cells. While all cell lines showed strong immunostaining for vimentin, treatment with 4-HPR for 8 days caused a marked decrease in staining for vimentin in all cell lines. In an in vitro assay, 4-HPR also caused inhibition of invasion by DU-145 cells in a dose-dependent manner. Furthermore, 4-HPR treatment was effective in significantly decreasing the abnormal nuclear staining for the tumor suppressor proteins p53 and pRb. Because 4-HPR decreased invasion-associated vimentin expression, inhibited invasion, and normalized p53 and pRb immunostaining, we propose that 4-HPR may be an effective agent for secondary and tertiary prevention, i.e. promotion and progression stages, respectively, of prostate cancer.

Genetic alterations and biological pathways in human bladder cancer pathogenesis

Human bladder cancers are heterogeneous. For example, at first presentation papillary transitional cell carcinomas (TCCs) are typically superficial and often multifocal. Papillary TCCs frequently recur, but most never progress to invasive TCC. In contrast, bladder carcinoma in situ (CIS) usually presents as a solitary flat lesion and, if left untreated, invariably progresses to invasive TCC. Some TCC are already invasive at the time of presentation. Squamous cell carcinoma (SCC) tends to present at a later stage than most TCCs and has a relatively aggressive clinical course. Multiple genetic alterations have been identified in invasive human bladder cancers and are present in different combinations and in different frequencies in the different manifestations of bladder cancer described above. A high percentage ( approximately 67%) of superficial papillary TCCs show early losses involving chromosome 9q, while very few show either a TP53 or a CDKN2/16 mutation. Thus, loss of 9q may be the earliest event in initiation of papillary TCC. In contrast, bladder CIS and SCC show relatively low percentages of 9q loss. However, approximately 65% of bladder CIS contain a TP53 alteration and approximately 67% of bladder SCC contain a CDKN2/p16 alteration. Mutations in these two tumor suppressor genes have powerful implications for loss of genome stability and cell growth regulation, respectively, consistent with the aggressive phenotypes of these cancers. Thus, these data suggest a model of bladder cancer pathogenesis in which the predominant genetic alteration may be the "initiating event" in cancer pathogenesis and may play a role in determining the biological potential of the tumor.

Minimal deletion of 3p13-->14.2 associated with immortalization of human uroepithelial cells

Immortalization and tumorigenic transformation of many human cell types, including human uroepithelial cells (HUCs), are frequently associated with loss of genetic material from the short arm of chromosome 3 (3p). In addition, losses of 3p have been observed in many human cancers including renal cell carcinoma, lung cancer, breast cancer, and bladder cancer. Genetic studies suggest that there are at least two regions on 3p in which tumor suppressor genes might be located, but the precise location of these genes is not known. We studied chromosome 3 losses that were specifically associated with immortalization of five independent human papilloma virus 16 (HPV16) E6- or E7-transformed HUCs. Cytogenetic analysis showed that the smallest common region of deletion was 3p14.1-->14.2. Fluorescence in situ hybridization using a 3p13-->14-specific yeast artificial chromosome (YAC) contig showed the precise localization of the breakpoints to be in 3p13 and 3p14.2, thus defining the smallest common overlap of 3p deletions in HPV16 E6- or E7-immortalized HUCs. These results suggest the presence in this region of genes involved in the control of senescence in vitro and possibly tumorigenesis in vivo.