Indomethacin and poly I:C in the inhibition of carcinogen-induced bladder cancer in an experimental animal model

Naproxen induces cell-cycle arrest and apoptosis in human urinary bladder cancer cell lines and chemically induced cancers by targeting PI3K

Naproxen [(S)-6-methoxy-α-methyl-2-naphthaleneacetic acid] is a potent nonsteroidal anti-inflammatory drug that inhibits both COX-1 and COX-2 and is widely used as an over-the-counter medication. Naproxen exhibits analgesic, antipyretic, and anti-inflammatory activities. Naproxen, as well as other nonsteroidal anti-inflammatory drug, has been reported to be effective in the prevention of urinary bladder cancer in rodents. However, potential targets other than the COX isozymes have not been reported. We examined potential additional targets in urinary bladder cancer cells and in rat bladder cancers. Computer kinase profiling results suggested that phosphoinositide 3-kinase (PI3K) is a potential target for naproxen. In vitro kinase assay data revealed that naproxen interacts with PI3K and inhibits its kinase activity. Pull-down binding assay data confirmed that PI3K directly binds with naproxen in vitro and ex vivo. Western blot data showed that naproxen decreased phosphorylation of Akt, and subsequently decreased Akt signaling in UM-UC-5 and UM-UC-14 urinary bladder cancer cells. Furthermore, naproxen suppressed anchorage-independent cell growth and decreased cell viability by targeting PI3K in both cell lines. Naproxen caused an accumulation of cells at the G1 phase mediated through cyclin-dependent kinase 4, cyclin D1, and p21. Moreover, naproxen induced significant apoptosis, accompanied with increased levels of cleaved caspase-3, caspase-7, and PARP in both cell types. Naproxen-induced cell death was mainly because of apoptosis in which a prominent downregulation of Bcl-2 and upregulation of Bax were involved. Naproxen also caused apoptosis and inhibited Akt phosphorylation in rat urinary bladder cancers induced by N-butyl-N-(4-hydroxybutyl)-nitrosamine.

COX-2 inhibitors and other nonsteroidal anti-inflammatory drugs in genitourinary cancer

Selective cyclooxygenase (COX)-2-inhibiting and other nonsteroidal anti-inflammatory drugs (NSAIDs) show promise for preventing and treating bladder and prostate cancers. In contrast to the strong NSAID epidemiology in colorectal cancer, the epidemiologic data on NSAIDs and genitourinary (GU) cancers are limited and mixed. However, a substantial body of preclinical in vitro and in vivo animal model data shows consistent NSAID activity in treating, and in some cases preventing, GU cancers and begins to address the mechanisms behind this activity (eg, involving Akt and ERK2 in the prostate). Many preclinical and clinical NSAID studies currently under way are helping to resolve the best type (selective or nonselective COX inhibitors or non-COX inhibitors), dose and duration of NSAID treatment for prevention in the GU setting. Future studies likely will focus on clarifying the NSAID mechanisms behind and developing NSAID combinations for both treating and preventing GU cancers.

Acetylsalicylic acid inhibition of n-butyl-(4-hydroxybutyl)nitrosamine-induced bladder carcinogenesis in rats

We examined the effect of acetylsalicylic acid (ASA) on n-butyl-(4-hydroxybutyl)nitrosamine (BHBN)-induced bladder carcinogenesis in male Wistar rats. Of 29 rats that received 0.05% BHBN in their drinking water for 9 weeks, 8 developed bladder cancer. Only 1 out of 29 rats that received 0.1% ASA in their diet for 20 weeks, including the period of BHBN consumption, developed a tumor. That difference is statistically significant. Bladder weight was significantly higher in rats given BHBN than in controls and in rats given both BHBN and ASA. We conclude that ASA inhibits BHBN-induced bladder carcinogenesis.

Prophylaxis and therapy of an experimental bladder cancer with biological response modifiers

We have previously reported that the intraperitoneal injection of viable bacillus Calmette-Guerin (BCG) reduces the incidence of tumor takes and the rate of tumor growth and also increases tumor regression rate and survival in C3H/HeN mice challenged with the syngeneic MBT-2 bladder cancer. We have now investigated the immunoprophylactic effect of BCG and other biological response modifiers. Groups of 12 to 15 female C3H/HeN mice were challenged with 5 X 10(5) MBT-2 viable cells and treated with BCG, poly I:C, tilorone, levamisole or a combination of these agents. Appropriate controls were included in each experiment. In this study we confirmed previous findings that BCG alone is effective in prophylaxis and can also decrease the rate of tumor growth in those animals not protected against tumor takes. Both i.p. levamisole and oral tilorone lacked activity against the MBT-2 tumor. A single i.p. injection of poly I:C was also ineffective although its repeated administration reduced the rate of tumor growth and induced a significant number of tumor regressions. Combined therapy of BCG with either levamisole or tilorone offered no therapeutic advantage over BCG alone. Heat-inactivated BCG also failed to induce anti-tumor activity in C3H/HeN mice challenged with MBT-2 cells. These results indicate that live BCG remains the most active immunoprophylactic and immunotherapeutic agent against the MBT-2 murine bladder cancer. Furthermore, the anti-tumor effect of viable BCG is not potentiated further by the addition of other immune modulating agents.