Function And Mechanism Of Brusatol In Melanoma

Background: Cutaneous melanoma remains the deadliest skin cancer,one of the most prevalent cancers in the Western world,and is a highly aggressive skin malignancy with a poor prognosis for patients.Most melanoma originates from congenital melanocytic nevi or is caused by a family history of melanoma.Five years ago,the Melanoma Research Foundation(MRF)evaluated the challenges and opportunities facing the melanoma research community and melanoma patients.Since then,significant progress has been made in both basic and clinical research.However,the incidence,recurrence and mortality rates of melanoma remain unacceptably high and significant challenges remain.In 2021,there were an estimated 106,110 new melanoma cases and 7180 melanoma-related deaths in the United States.The incidence of melanoma is on the rise,with melanoma ranking third among all cancers in terms of years of life lost.With the Nobel Prize awarded by Ms.Tu Youyou,a famous scientist in China,for her discovery of the role of artemisinin in malaria,the role of traditional Chinese medicine in diseases has received worldwide attention,and research on traditional Chinese medicine has been actively carried out,and traditional Chinese medicine has become a major research hotspot.Ya-Dan-Zi also known as Brusatol.The chemical formula is C26H32O11.It is a lactone extracted from Chinese medicine Brucea javanica.In recent years,the number of literature reports on the role of Brusatol in anti-cancer has increased significantly compared with the past,and the mechanism of action of Brusatol in many types of cancer has been widely explored,but there are few studies on the role and mechanism of melanoma.Objective: We divided the experiment into three stages: in vitro experiment,in vivo tumorigenesis experiment,and molecular mechanism to explore the role and molecular mechanism of Brusatol in melanoma.Methods and results: In vitro experiments mainly detected the effects of Brusatol on cell viability,proliferation and migration ability,and apoptosis of melanoma cells by MTT and colony formation assays,transwell,Flow cytometric analysis,Immunohistochemistry(IHC)and other methods.It was found that Brusatol inhibited the proliferation and migration ability of melanoma cells and induced apoptosis;In vivo experiments were conducted to judge the effect of drugs on the tumorigenic ability of melanoma cells through subcutaneous tumorigenesis in mice.The results showed that Brusatol inhibited the tumorigenic ability of melanoma cells in vivo;The molecular mechanism experiments mainly used the construction of target plasmid,Lentivirus packaging and infection,RNA nd mi RNA sequencing analysis,western blotting,Chromatin immunoprecipitation(Ch IP),Promoter reporters and dual-luciferase,Propidium Iodide(PI)staining,Quantitative reverse transcription PCR,Luciferase and other experimental methods to obtain the significant downregulation of the expression of stearoyl-Co A desaturase 1(SCD1)in melanoma cells.Increasing SCD1 expression impairs the antitumor effect of Brusatol on melanoma cells.Subsequently,we found that the important transcription factor HOXB9 binds directly to the promoter of SCD1,facilitating its transcription.Overexpression of HOXB9 inhibits Brusatol-induced SCD1 reduction and promotes cell survival.In addition,our results show that mi R-122-5p increases significantly after Brusatol treatment and results in a decrease in HOXB9 in melanoma.Thus,a molecular signaling pathway was established for Brusatol to act on melanoma cells.Conclusion: In conclusion,our data suggest that the mi R-122-5p/HOXB9/SCD1 axis may play an important role in the antitumor effects of Brusatol,which may have potential clinical significance in melanoma treatment.