IL-1ß Inflammatory Cytokine-Induced TP63 Isoform ∆NP63α Signaling Cascade Contributes to Cisplatin Resistance in Human Breast Cancer Cells.

The mechanisms behind the induction of malignancy and chemoresistance in breast cancer cells are still not completely understood. Inflammation is associated with the induction of malignancy in different types of cancer and is highlighted as an important factor for chemoresistance. In previous work, we demonstrated that the inflammatory cytokine interleukin 1ß (IL-1ß)-induced upregulation of genes was associated with chemoresistance in breast cancer cells. Here, we evaluated the participation and the expression profile of TP63 in the induction of resistance to cisplatin. By loss-of-function assays, we identified that IL-1ß particularly upregulates the expression of the tumor protein 63 (TP63) isoform ΔNP63α, through the activation of the IL-1ß/IL-1RI/ß-catenin signaling pathway. Upregulation of ΔNP63α leads to an increase in the expression of the cell survival factors epidermal growth factor receptor (EGFR) and phosphatase 1D (Wip1), and a decrease in the DNA damage sensor, ataxia-telangiectasia mutated (ATM). The participation of these processes in the increase of resistance to cisplatin was confirmed by silencing TP63 expression or by inhibition of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) activity in the IL-1ß/IL-1RI/ß-catenin signaling pathway. These data reinforced the importance of an inflammatory environment in the induction of drug resistance in cancer cells and uncovered a molecular mechanism where the IL-1ß signaling pathway potentiates the acquisition of cisplatin resistance in breast cancer cells.

Knockdown of NF-kB1 by shRNA Inhibits the Growth of Renal Cell Carcinoma In Vitro and In Vivo

Renal cell carcinoma (RCC) accounts for approximately 2%-3% of human malignancies and is the most aggressive among urologic tumors. Biological heterogeneity, drug resistance, and chemotherapy side effects are the biggest obstacles to the effective treatment of RCC. The NF-kappa B transcription factor is one of several molecules identified to be responsible for the aggressive phenotype of this tumor. In the past decade, several studies have demonstrated the activation of NF-kappa B in RCC, and many have implicated NF-kappa B1 (p50) as an important molecule in tumor progression and metastasis. In the present study, a lentivirus was used to deliver shRNA targeting NF-kappa B1 into mouse RCC (Renca) cells. It was determined that the knockdown of the NF-kappa B1 gene led to a reduction in cell proliferation and late apoptosis/necrosis in vitro. Flow cytometry analysis demonstrated G(2)/M arrest in the cells. In addition, immunoblotting analysis revealed a significant increase in cyclin B1 and Bax. In vivo experiments showed that Renca-shRNA-NF-kappa B1 cells have significantly diminished tumori genicity. Moreover, immunohistochemical analysis revealed an increase in necrotic areas of Renca-shRNA-NF-kappa B1 tumors. Thus, this study indicates that downregulation of NF-kappa B1 can suppress RCC tumorigenesis by inducing late apoptosis/necrosis. Therefore, NF-kappa B1 may be a potential therapeutic target for RCC.