Selective Susceptibility of Human Bladder Transitional Cell Carcinoma T24 Cells towards NBD Peptide

Bladder cancer is a recurrent disease that often develops chemoresistance and is on the rise in developing countries. After diagnosis surgery followed by immunotherapy and/or chemo- radiation therapy are the available treatments. These treatments do not provide protection against disease progression or recurrence thus highlighting the need to identify and develop drugs that are capable of inhibiting bladder cancer. T24 cell line (human bladder transitional cell carcinoma) was treated with NEMO Binding Domain (NBD) peptide and tested for its cytotoxicity, cell cycle inhibition, apoptosis and migration, in vitro. The cytotoxicity of NBD peptide was tested on non-cancerous cells (NIH-3T3-L1, CHO, Vero) and the peptide localization in T24 cells was confirmed using confocal microscopy. The effects of NBD peptide and the standard drugs (cisplatin, gemcitabine) were compared with untreated control. Peptide based chemotherapy for human bladder cells was tested that include combinations of NBD and standard drugs. Statistical significance was assessed between the different treatment groups. The viability of T24 cells after NBD peptide treatment was reduced to 50% at a dose of 18.5 µM after 48 h. The NBD peptide elicited selective cytotoxicity dose-dependently in T24 cells while being non-toxic on normal (non-cancer) cell lines. Sub G0-G1 accumulation of T24 cells was seen where they underwent necrosis and lost the ability to migrate when treated with 100 µM NBD. T24 cell death increased to ~78% when treated with a combination of NBD with cisplatin and gemcitabine (standard drugs) as opposed to ~50% when treated with NBD peptide alone. NBD peptide exhibits specific anti-cancer activity on T24 cells in vitro and found to be non-cytotoxic to select normal cell lines. Combining NBD with standard drugs demonstrated excellent inhibition of malignant growth than the individual anti-neoplastic agents.