RESUMO
In traditional Chinese Medicine, the preparation Danggui Longhui Wan has been used for years in the treatment of chronic myelocytic leukemia. The compound indirubin has been shown to be the active constituent. A cell permeable derivative, indirubin-3'-monoxime, is a selective and potent inhibitor of cyclin-dependent kinases (cdk). The ability of indirubin-3'-monoxime to induce apoptosis and tumor cell death in transitional cell cancer cell lines was investigated here. The growth-inhibitory properties were evaluated by EZ4U, a cytotoxic assay; apoptosis induction was determined by immunoblotting of cleaved PARP and flow cytometry of Annexin-V/PI staining during treatment. To evaluate further the underlying molecular action of indirubin-3'-monoxime on the cell cycle, the levels of cdk-1 and survivin, a mitotic spindle checkpoint and apoptosis-regulating protein, respectively, were additionally determined by flow cytometry and immunoblotting. The results indicated that indirubin-3'-monoxime induced reversible growth arrest in all four cell lines and an increase of apoptosis in two of them. The treatment with indirubin-3'-monoxime increased the expression of survivin almost four times in the RT4 cells and more than doubled it in the RT112 and T24 cells. In the SUP cells, the expression of survivin increased more than seven-fold after 72-h incubation. No clear correlation between the low apoptosis induction rate and extent of survivin expression was found. Cdk expression was not significantly altered by indirubin-3'-monoxime. In summary, indirubin-3'-monoxime might be a promising candidate for targeted cancer therapy, however, its molecular action remains to be further evaluated.
Assuntos
Apoptose/efeitos dos fármacos , Carcinoma de Células de Transição/tratamento farmacológico , Indóis/farmacologia , Proteínas Associadas aos Microtúbulos/biossíntese , Proteínas de Neoplasias/biossíntese , Oximas/farmacologia , Neoplasias da Bexiga Urinária/tratamento farmacológico , Apoptose/fisiologia , Proteína Quinase CDC2/biossíntese , Proteína Quinase CDC2/genética , Carcinoma de Células de Transição/genética , Carcinoma de Células de Transição/metabolismo , Carcinoma de Células de Transição/patologia , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Proteínas Inibidoras de Apoptose , Proteínas Associadas aos Microtúbulos/genética , Proteínas de Neoplasias/genética , Survivina , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/fisiologia , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/metabolismo , Neoplasias da Bexiga Urinária/patologiaRESUMO
OBJECTIVES: Indirubin-3'-monoxime, which is a selective and potent inhibitor of cyclin-dependent kinases (CDKs) has shown preclinical activity in several human cancer cells. This study investigated if indirubin-3'-monoxime can induce apoptosis and tumor cell death in 3 human (A498, CAKI-1, CAKI-2) and 1 murine renal cell cancer (RENCA) cell line. METHODS: The growth inhibitory and apoptosis induction properties were evaluated by EZ4U, a cytotoxic assay and by flow cytometry of annexin-V/PI staining during treatment with doses ranging from 5.0 to 15.0 µM indirubin-3'-monoxime over 72 hours. To further establish the underlying molecular targets of indirubin-3'-monoxime, survivin, a major anti-apoptotic protein was additionally determined by intracellular flow cytometry. RESULTS: Our results show that indirubin-3'-monoxime induces growth arrest and apoptosis in all renal cell cancer (RCC) cell lines. All RCC lines expressed survivin. However, a clear correlation between apoptosis induction and expression of survivin was not found. CONCLUSIONS: As treatment of metastatic renal cell cancer (mRCC) remains a challenge, and the need for continuing assessment of novel agents in the treatment of this disease is mandatory. Indirubin-3'-monoxime seems to be a candidate for further evaluation.