Arbutin exerts anticancer activity against rat C6 glioma cells by inducing apoptosis and inhibiting the inflammatory markers and P13/Akt/mTOR cascade

Abstract

Gliomas are a type of brain cancer that occurs in the supporting glial cells of the brain. It is highly malignant and accounts for 80% of brain tumors with high mortality and morbidity. Phytomedicines are potent alternatives for allopathic drugs which cause side effects. They have been used from ancient times by traditional Chinese, Ayurveda, and Siddha medicine. Arubtin is a glycoside phytochemical extracted from plants and belongs to the family of Ericaceae. Arbutin possesses various pharmacological properties such as anti-inflammatory, antioxidant, antitumor, and so on. Hence in the present study, we analyzed the anticancer potency of arbutin against rat C6 glioma cells. Rat C6 glioma cells were procured from American Type Culture Collection and the cells were cultured in Roswell Park Memorial Institute-1640 medium. To assess the cytotoxicity effect of the arbutin against C6 glioma cells, an 3-(4,5-dimethylthiazol-2-yl)−2,5-diphenyl tetrazolium bromide test was performed with different doses from 10 to 60 µM. Arbutin effectively induced apoptosis in the cells and the IC 50 dose was obtained at 30 µM.For further studies, we selected the 30 µM IC 50 dose and a higher dose of 40 µM.Reactive oxygen species (ROS) generated were analyzed with DCFDA/H2DCFDA stain and the destruction of mitochondrial membrane permeability which is the initiator of apoptosis was analyzed with a cationic stain Rhodamine 123. Dual staining with acridine orange and ethidium bromide was performed to assess the viable and dead cells. Cell adhesion properties of glioma cells were analyzed with Matrigel assay. The apoptotic, inflammatory, and phosphoinositide 3-kinase (PI3K)/ mammalian target of rapamycin (mTOR) signaling molecules were analyzed with quantitative polymerase chain reaction (qPCR) analysis to confirm the anticancer effect of arbutin. Arbutin generated excessive ROS and disrupted the mitochondrial membrane, which induced apoptosis in cells, it also inhibited the cell adhesion property of C6 glioma cells. qPCR analysis clearly indicates arbutin increases the apoptotic genes and decreased the inflammatory and PI3K/mTOR signaling © 2021 Wiley Periodicals LLC molecules. Overall, our results authentically confirm that arbutin can be a potent alternative for treating glioma.

Arbutin: Occurrence in Plants, and Its Potential as an Anticancer Agent

“…In addition to its skin whitening property which has been known for at least seven decades, arbutin (1) has been shown to possess various other therapeutically relevant biological properties, e.g., antioxidant, antimicrobial and anti-inflammatory [164,165]; it also has the potential as an anticancer agent [166][167][168][169][170][171][172][173][174][175][176][177][178][179][180][181]. Information obtained from the published literature on arbutin shows that this compound possesses cytotoxic properties against several human cancer and tumor cell lines including bladder, bone, brain, breast, cervical, colon, gastric, liver, prostate and skin cancers (Table 2) [166][167][168][169][170][171][172][173][174][175][176][177][178][179][180][181]. Most of these activities have been demonstrated in vitro, and in some cases, plausible mechanisms of action, e.g., apoptosis, have been identified (Table 2).…”

“…In vitro [167,168] Breast cancer Cytotoxicity of arbutin containing methanolic extract against MDA-MB-231 and T-47D breast cancer cells.…”

“…In vitro [181] published literature on arbutin shows that this compound possesses cytotoxic properties against several human cancer and tumor cell lines including bladder, bone, brain, breast, cervical, colon, gastric, liver, prostate and skin cancers (Table 2) [166][167][168][169][170][171][172][173][174][175][176][177][178][179][180][181]. Most of these activities have been demonstrated in vitro, and in some cases, plausible mechanisms of action, e.g., apoptosis, have been identified (Table 2).…”

“…In a recent study on the effect of arbutin on brain tumor, it was found that it could kill C6 glioma cells by inducing apoptosis (IC 50 = 30 mM) and inhibiting the inflammatory markers and P13/AKT/mTOR cascade [167]. It should be noted that P13/AKT/mTOR is an intracellular signaling pathway that regulates the cell cycle and, thus, is linked to cell proliferation.…”

“…Like bladder cancer, over 11,000 people are diagnosed with primary brain tumors every year in the UK, and a half of those are cancerous [186]. A recent study [167] suggested that arbutin could be a potential anti-brain tumor drug for the treatment of glioma. However, further studies are obviously necessary in this regard.…”