Effects of nanostructured formulations of immunomodulator P-MAPA in Non-Muscle Invasive Bladder Cancer (NMIBC) Progression

Abstract

The low efficacy of treatment and high rates of bladder cancer (BC) recurrence may be related to the low effects of these therapies on the mechanisms of tissue repair, angiogenesis, and reactive oxygen species (ROS). Furthermore, current drugs have low residence time and low penetration in the urothelium, contributing to the reduction of therapeutic response. Nowadays, the most effective therapy for BC is the Bacillus Calmette-Guerin (BCG) immunotherapy, which causes side effects of different intensities from irritative symptoms to serious systemic reaction, which contributes to treatment interruption besides increasing cancer index recurrence after treatment, up to 31%. Thus, the development of new molecules or improving drugs that can increase penetration and residence time of drugs in the urothelium, with consequent reduction of intravesical instillation, rate of recurrence, and progression of tumor and side effects are very relevant. In this scenario, we highlight the immunomodulator P-MAPA, which for its great versatility and minimal cytotoxicity opens a new perspective to the treatment of some cancers types, including BC. Thus, the aims of this study were to characterize and to compare the molecular and histopathological effects of P-MAPA formulations nanostructured with BCG immunotherapy in the treatment of BC progression induced in rats and to establish the effects of these therapeutic strategies in factors inducers and repairers of cell damage, angiogenesis, and ROS. For this, first of all, the P-MAPA microcrystals will be canonized and stabilized with chitosan, to increase the residence time of P-MAPA and its penetration in the urothelium, reducing thereby the number of infusions and increasing the effectiveness of this immunomodulator. The antitumor activity of nanocrystals of P-MAPA with BCG immunotherapy, Fischer 344 female rats will be used. These animals will be submitted to BC chemical induction by instillation of 1.5 mg/kg of N-methyl-N-nitrosourea (MNU) every 15 days, a total of 4 doses. Two weeks after the last dose of MNU, the animals will be divided into 4 experimental groups, namely: Control Group (Group 1): It will receive an intravesical dose of 0.3 mL of 0.9% saline for 6 weeks; MNU Group (Cancer - Group 2): It will receive an intravesical dose of 0.3 mL of 0.9% saline for 6 weeks; MNU+BCG (Group 3): It will receive a dose of intravesical CFU 106 - 40 mg of BCG diluted in 0.3 mL of 0.9% saline for 6 weeks consecutive; MNU+P-MAPA-nano Group (Group 4): It will receive an intravesical dose of 5 mg/kg of P-MAPA-nano dissolved in 0.3 ml of 0.9% saline for 6 weeks. After 16 weeks of treatment, the animals will be euthanized and the urinary bladders collected and analyzed for histopathological and Western Blotting analyses.(AU)