The supernatant was discarded and culture medium containing different concentrations of protosappanin B was added (final concentration: 100, 150, 200, 250, or 300?g/mL). the proportion of S-phase cells and proliferation index. A proteomics analysis showed that protosappanin B modulated a number of genes involved in the cell cycle. In conclusion, protosappanin B inhibits the proliferation and promotes the apoptosis of T24 and 5637 Brexpiprazole human bladder cancer cells in a concentration-dependent manner, possibly via interference with cell cycle regulation, preventing G1-to-S transition. Introduction Bladder cancer is one of the most common malignant tumors, ranked eleventh among malignant cancers in terms of incidence1, and is associated with high mortality1. It has been estimated that, in 2012, around 430,000 new cases of bladder cancer occurred worldwide and over 165,000 people died from it2. Bladder cancer affects men more commonly than women, and smoking is recognized as an important risk factor3. The incidence of bladder cancer in China during the last 10 years has shown an increasing trend both in urban and rural areas, and this may be associated with the increases in tobacco consumption, level of industrialization, and population aging4. Bladder transitional cell carcinoma is the most frequent type, accounting for 95% of the cases. Around 30% of patients with bladder cancer present with an invasive form of the disease associated with a high risk of metastasis5. Various strategies are currently available for the management Rabbit polyclonal to BMPR2 of bladder cancer, including transurethral resection of bladder tumor (TURBT), radical cystoprostatectomy, radiotherapy, chemotherapy, and intravesical therapy5. Among these, the main treatment approaches both in China and abroad is surgery combined with intravesical chemotherapy. There have been several recent advances in the diagnosis and treatment of bladder cancer6, including research on new targeted therapies7. Nevertheless, the available surgical and medical therapies are associated with significant adverse Brexpiprazole effects Brexpiprazole on the quality of life and with high recurrence and mortality rates2. In particular, the chemotherapeutic drugs (methotrexate, vincristine, doxorubicin, cisplatin, and cytosine) and biological therapies (BCG,?immunologic and inactivated bacterial solutions) currently used in clinical practice are associated with high costs, significant adverse effects, and various complications8. These limitations highlight the need to develop novel treatment approaches. Traditional Chinese medicine (TCM) has a long history in the treatment of cancer, with many components of TCMs being reported to have anti-cancer properties9. With the increasing application of molecular biology in oncology research, there has been considerable interest in studying the anti-tumor effects of TCMs and Brexpiprazole identifying the responsible compounds and possible underlying mechanisms. Lignum Sappan, derived from the heartwood of L., is commonly used in TCM and promotes blood circulation for removing obstruction in collaterals. In addition to anti-inflammatory10, anti-allergy11, anti-fungal12, anti-viral13, anti-oxidative14, and vasorelaxant15 properties, Lignum Sappan has also been shown to have anti-cancer effects. Indeed, Lignum Sappan extracts have been reported to reduce the viability of a wide variety of cancer cells16, including head and neck17, sarcoma18, hepatocellular carcinoma18, lung adenocarcinoma18, colorectal adenocarcinoma18, gastric cancer19, leukemia20, and ovarian cancer21 cell lines. Lignum Sappan has also been shown to inhibit tumor growth in a mouse xenograft model bearing S180 sarcoma cells18. In recent years, there has been considerable interest in identifying the active components of Lignum Sappan and studying the mechanisms by which these components inhibit tumor growth. Brazilin is an important active component of Lignum Sappan and has been found to exert an anti-cancer effect. Brazilin has been shown to inhibit the proliferation of human bladder cancer T24 cells22 and induce the apoptosis of multiple myeloma U266 cells23, glioma U87 cells24, sarcoma S180 cells18, hepatocellular carcinoma HepG2 cells18, lung adenocarcinoma H522 cells18, colorectal adenocarcinoma Colo205 cells18, and head and neck squamous cell carcinoma Cal27 cells25. Protosappanin B is another major component of Lignum Sappan and is listed by the Chinese Pharmacopoeia26 as an indicator of the quality of Lignum Sappan preparations. At present, there are very few published studies describing the effects of protosappanin B. Anti-inflammatory27, anti-bacterial28, and anti-oxidative29 properties of protosappanin B have been reported, and pharmacokinetic and bioavailability studies have been conducted in rodents30,31. Protosappanin B has also been shown.