RESUMO
BACKGROUND: Licochalconce (LC) H is an artificial compound in the course of synthesizing LCC in 2013. So far, few studies on the effects of LCH have been found in the literature. Despite progress in treatment modalities for oral cancer, the cure from cancer has still limitations. PURPOSE: The effects of LCH were investigated on human oral squamous cell carcinoma (OSCC) cells to elucidate its mechanisms. STUDY DESIGN: We explored the mechanism of action of LCH by which it could have effects on JAK2/STAT3 signaling pathway. METHODS: To confirm LCH anti-cancer effect, analyzed were MTT assay, DAPI staining, soft agar, kinase assay, molecular docking simulation, flow cytometry and Western blotting analysis. RESULTS: According to docking and molecular dynamics simulations, the predicted pose of the complex LCH and JAK2 seems reasonable and LCH is strongly bound to active JAK2 with opened activation loop. The LCH inhibitor is surrounded by specific ATP-binding pocket in which it is stabilized by forming hydrogen bonds and hydrophobic interactions. It is shown that LCH plays as a competitive inhibitor in an active state of JAK2. LCH caused a dose-dependent decrease in phosphorylation of JAK2 and STAT3. More interestingly, LCH suppressed JAK2 kinase activity in vitro by its direct binding to the JAK2. LCH significantly inhibited the JAK2/STAT3 signaling pathway, causing the down-regulation of target genes such as Bcl-2, survivin, cyclin D1, p21 and p27. In addition, LCH inhibited cell proliferation and colony formation of OSCC cells in a dose- and time-dependent manner, as well as induction of cell apoptosis through extrinsic and intrinsic pathway. The induction of apoptosis in OSCC cells by LCH was evident in the increased production of ROS, loss of mitochondrial membrane potential, release of cyto c, variation of apoptotic proteins and activation of caspase cascade. CONCLUSION: LCH not only induces apoptosis in OSCC cells through the JAK/STAT3 signaling pathway but also inhibits cell growth. It is proposed that LCH has a promising use for the chemotherapeutic agent of oral cancer.
Assuntos
Apoptose/efeitos dos fármacos , Carcinoma de Células Escamosas/patologia , Chalconas/farmacologia , Janus Quinase 2/metabolismo , Neoplasias Bucais/patologia , Carcinoma de Células Escamosas/tratamento farmacológico , Caspases/metabolismo , Ciclo Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Chalconas/química , Ciclina D1/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Simulação de Acoplamento Molecular , Neoplasias Bucais/tratamento farmacológico , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Survivina/metabolismoRESUMO
Earlier studies have shown that tolfenamic acid (Tol) exhibits anticancer activity in several cancer models by inhibiting tumor growth and angiogenesis. However, the chemopreventive effect of Tol on a cervical cancer model and the underlying mechanism of action are unknown. In this study, Tol was found to inhibit cell proliferation by inducing apoptosis without affecting cyclo-oxygenase 2 expression, but ampiroxicam did not. Tol decreases the specificity protein 1 (Sp1) mRNA and its promoter activity in KB cervical cancer cells, and the downregulation of Sp1 protein by affecting several proteins that contain GC-rich sites on their promoters. Studies using small interference RNA and an Sp1-specific inhibitor (mithramycin A) confirmed that the decrease in Sp1 by Tol affects survivin and p27. Tol also inhibited tumor growth and Sp1 protein in athymic nude mice xenografts. These results show that Tol could be a potent anticervical cancer drug that acts by regulating Sp1 protein and its downstream pathways.
