Novel ANO1 Inhibitor from Mallotus apelta Extract Exerts Anticancer Activity through Downregulation of ANO1

Abstract

Anoctamin1 (ANO1), a calcium-activated chloride channel, is frequently overexpressed in several cancers, including human prostate cancer and oral squamous cell carcinomas. ANO1 plays a critical role in tumor growth and maintenance of these cancers. In this study, we have isolated two new compounds (1 and 2) and four known compounds (3–6) from Mallotus apelta. These compounds were evaluated for their inhibitory effects on ANO1 channel activity and their cytotoxic effects on PC-3 prostate cancer cells. Interestingly, compounds 1 and 2 significantly reduced both ANO1 channel activity and cell viability. Electrophysiological study revealed that compound 2 (Ani-D2) is a potent and selective ANO1 inhibitor, with an IC50 value of 2.64 μM. Ani-D2 had minimal effect on cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel activity and intracellular calcium signaling. Notably, Ani-D2 significantly reduced ANO1 protein expression levels and cell viability in an ANO1-dependent manner in PC-3 and oral squamous cell carcinoma CAL-27 cells. In addition, Ani-D2 strongly reduced cell migration and induced activation of caspase-3 and cleavage of PARP in PC-3 and CAL-27 cells. This study revealed that a novel ANO1 inhibitor, Ani-D2, has therapeutic potential for the treatment of several cancers that overexpress ANO1, such as prostate cancer and oral squamous cell carcinoma.

Purple Corn Extract Improves Benign Prostatic Hyperplasia by Regulating Prostate Cell Proliferation and Apoptosis

“…The mRNA expression level of 5AR2 was markedly elevated in the TP group, whereas it decreased in the Fina, PCE 10, and 50 groups (Figure C). ANO1, also known as calcium-activated chloride channel, is widely expressed in diverse tissues and regulates many physiological activities, including epithelial cell secretion and cell proliferation . Since increased ANO1 with androgen binding to AR affects the development of BPH, the effect of PCE on ANO1 mRNA expression was also determined.…”

Cinobufagin Exerts Anticancer Activity in Oral Squamous Cell Carcinoma Cells through Downregulation of ANO1

“…Natural products have been a productive source for producing lead compounds and therapeutic agents, and some natural products potently and directly block ANO activity [ 32 , 33 , 38 , 39 ]. Therefore, we performed a cell-based screening using a natural product library containing 730 natural products to identify novel compounds inducing downregulation of ANO1.…”

“…A number of previous studies have shown that inhibition or downregulation of ANO1 induces apoptosis in various cancer cell lines [ 32 , 33 , 45 , 46 , 47 ]. Here, we explore whether cinobufagin induces apoptosis in CAL-27 cells highly expressing ANO1.…”

“…Protein sample preparation protocol was described previously [ 33 ]. Protein samples were separated using 4–12% Tris Glycine Precast Gel (KOMA BIOTECH, Seoul, Korea).…”

“…In previous studies, we identified several potent inhibitors of ANO1, such as Ani9, Ani9-5f, Ani-D2, luteolin and idebenone, which potently inhibited the chloride channel activity of ANO1, and Ani9-5f, Ani-D2, luteolin and idebenone significantly reduced cell proliferation and migration and induced apoptosis in several cancer cells highly expressing ANO1 [ 29 , 30 , 31 , 32 , 33 ]. However, all of these inhibitors and other previous ANO1 inhibitors strongly block the chloride channel activity of ANO1, which plays a pivotal role in normal physiological function.…”