Nonsteroidal anti-inflammatory drugs increase expression of inducible COX-2 isoform of cyclooxygenase in spinal cord of rats with adjuvant induced inflammation.

Several lines of evidence have accumulated that release of excitatory amino acids, nitric oxide and prostaglandin E2 (PGE2) play a critical role in the development of peripheral tactile and thermal hypersensitivity in chronic inflammatory pain models. Synthesis of PGE2 is controlled by cyclooxygenase (COX), either the COX-1 or COX-2 isoform. COX-2 plays a central role in the inflammatory reactions. The relationship between central sensitization of a complete Freund's adjuvant (CFA) induced inflammation and expressions of COX-2 were assessed in a rat model of CFA injection induced inflammation. Moreover, the time course of analgesia and spinal COX-2 expression following intrathecal (IT) injection with a nonspecific COX inhibitor (ketorolac) and COX-2 inhibitor (celecoxib) were determined using Western blot and immunohistochemistry. COX-2 protein was slightly increased in the lumbosacral spinal cord at 24 h following subcutaneous injection of CFA in the plantar surface of the left hindpaw (p > 0.05). COX-1 was not detected in normal and CFA injection rats. Surprisingly, IT ketorolac or celecoxib significantly increased spinal COX-2 levels at 1 h post-IT injection (p < 0.05) both in inflamed and non-inflamed rats. Then, spinal COX-2 levels declined at 3 and 6 h post-IT injection. These results provide strong in vivo evidence that COX-2 activity but not level may play a central role in the Freund's adjuvant-induced inflammation. However, spinal COX-2 level was upregulated following IT ketorolac and celecoxib injection. These data implies that suppression of PGE2 activity may induce the expression of spinal COX-2 in Freund's adjuvant-induced pain model. Our study concludes that IT administration of COX-2 inhibitor or nonspecific COX inhibitor is associated with significant short-term increase in spinal COX-2 expression.

Association of overexpressed proline-directed protein kinase F(A) with chemoresistance, invasion, and recurrence in patients with bladder carcinoma.

BACKGROUND: It has been shown previously that proline-directed protein kinase F(A) (PDPK F(A)) is overexpressed in various human malignancies compared with its expression in normal controls, and the suppression of overexpressed PDPK F(A) is capable of inhibiting the growth of various types of human carcinoma cells, suggesting a role for this PDPK in human malignancies. In this report, the authors combine immunohistologic, molecular, cellular, and clinicopathologic studies to demonstrate further an essential critical role for overexpressed PDPK F(A) in bladder carcinoma invasion, chemoresistance, and poor prognosis. METHODS: The expression and localization of PDPK F(A) were analyzed by the immunohistochemical staining of specimens obtained from patients with primary transitional cell carcinoma (TCC) of the bladder. The stable antisense clones of human bladder carcinoma cells with specific suppression of overexpressed PDPK F(A) were established for invasion and chemosensitivity studies. RESULTS: The immunohistochemical study revealed that PDPK F(A) was overexpressed preferentially in the invasive bladder carcinoma tissues. It was found that the stable antisense clones with specific suppression of overexpressed PDPK F(A) to approximately 40% of the parental control level were capable of inhibiting the invasive activity and simultaneously enhancing the chemosensitivity of bladder carcinoma cells to various therapeutic drugs, such as vinblastine, vincristine, paclitaxel, and bleomycin. Clinicopathologic studies also revealed a correlation between overexpressed PDPK F(A) and disease recurrence/survival in patients with primary TCC (P < 0.05). CONCLUSIONS: Taken together, the results demonstrate an essential critical role of overexpressed PDPK F(A) in invasion, chemoresistance, and poor prognosis. Suppression of overexpressed PDPK F(A) may provide a new potential target for therapeutic intervention aimed at preventing chemoresistance, disease progression, and recurrence in patients with bladder carcinoma.