Introduction

Bladder cancer (BCa) is the most common urological carcinoma with more than 4.3 × 105 new cases per year [1, 2]. BCa is complex in histopathological characteristics and is usually divided into two independent groups including muscle invasive and non-muscle invasive BCa [3]. The natural storage of urine in the bladder makes intravesical administration the most effective route of medication and treatment besides surgical resection, which has led to researchers have never stopped exploring new drugs for bladder cancer. A distinctive biological reagent named as Bacille Calmette-Guérin (BCG) vaccine also received great success in bladder cancer treatment. European Association of Urology (EAU) has recommended BCG bladder irrigation as one of the preferred adjuvant treatments for non-muscle invasive bladder cancer in 2018 [4]. Despite extensive research achievements have been successfully applied, the survival of BCa patients is still not fully satisfactory. The major factor is toxic side effects on off-target organs with the treatment of disease. It has been reported that the 5-year mortality rate of the muscle invasive BCa patients with lymph node (LN) metastasis is more than 77% [5]. Thus, finding a new antineoplastic drug with higher bioavailability is currently urgent.

Plant-derived drugs (PDDs) have been used to anti-cancer applications for thousands of years [6,7,8]. Our group has screened out a series of BCa chemotherapeutic PDDs, and their anti-tumor mechanisms were also investigated. For instance, capsaicin could suppress the tumorigenesis of BCa xenograft in vivo via FOXO3a mediated pathways [

Conclusions

In our study, we found PL inhibits the proliferation of T24 and UMUC3 cells in vivo and in vitro, which may play a role through several downstream effectors of PI3K/AKT/mTOR signaling pathway promoting the cell cycle arrest and apoptosis. Meanwhile, we consider that PL may inhibit the migration of bladder cancer cells via EMT suppression and induce ROS generation to make cell apoptosis. This work screened out PL with relatively good anti-tumor activity in human bladder cancer. It provides a reference for future clinical trials and new drug research and development, adds a choice for multi-drug combination to prevent drug resistance.