Scutellaria Radix Promotes Apoptosis in Non-Small Cell Lung Cancer Cells via Induction of AMPK-Dependent Autophagy

Abstract

Scutellaria Radix (SR) is an herb traditionally used in Asian countries to treat inflammatory diseases. Recent studies report that SR exhibits anticancer activities in various types of tumors. In this study, we investigated the apoptotic and autophagic effect of SR in non-small cell lung cancer (NSCLC), the leading cause of cancer-associated death. Treatment of SR in two NSCLC cell lines, H358 and H2087 cells resulted in suppressed cell viability. Western blot assays showed increased expressions of Bcl-2-associated X protein (Bax), cleaved-caspase 3 and cleaved-Poly ADP ribose polymerase (PARP), key factors of apoptosis. Co-treatment of SR with a caspase inhibitor Z-VAD led to nullification of the antiproliferative effect, suggesting the role of apoptosis in the action mechanism of SR. Further experiments revealed autophagy was involved in the effect of SR. SR-treated NSCLC cells expressed increased ratio of microtubule-associated protein 1A/1B-light chain 3 (LC3)-II/LC3-I. When chloroquine was co-treated with SR, this ratio was further increased, indicating SR treatment induced autophagy in NSCLC cells. Interestingly, loss of autophagy by 3-Methyladenine (3-MA) co-treatment suppressed SR-induced apoptosis. We then evaluated the relevance of AMP-activated protein kinase (AMPK) in the autophagic/apoptotic process in NSCLC by SR treatment. Immunoblot assays showed increased phosphorylation of AMPK[Formula: see text] and P70-S6 kinase in SR-treated H358 and H2087 cells. Under AMPK-inhibited conditions by compound C, SR treatment failed to induce both autophagy and apoptosis. Taken together, this study identifies the positive effect of SR in H358 and H2087 cells by inducing apoptosis via AMPK-dependent autophagy. Thus, our results suggest the potential use of SR as a novel therapeutic strategy for NSCLC patients.

An In Vitro Evaluation of the Molecular Mechanisms of Action of Medical Plants from the Lamiaceae Family as Effective Sources of Active Compounds against Human Cancer Cell Lines

“…The activation of the mTOR pathway was promoted by Ocimum basilicum leaf extract in MCF-7 cells with p70S6K, which is a downstream target kinase [ 181 ]. Similar features were shown for Scutellaria baicalensis root extract in H358 and H2087 cell lines [ 165 ].…”

“…The induction of caspase-3 and/or caspase-7 cleavage was also observed for Melissa officinalis leaf extracts against HT-29 and T84 cells [ 145 ] and for Origanum majorana leaf extract against HT-29 cells [ 171 ]. Dracocephalum palmatum leaf extract also induced apoptosis according to the intrinsic pathway via the upregulation of activated caspase-3 in PC-3 cells [ 169 ]; the same was observed for Nepeta cataria aerial parts on PC-3 cells [ 172 ] and Scutellaria baicalensis whole body extract on H358 and H2087 cell lines [ 165 ].…”

“…Changes in the level of Bcl-2 family members may result in the release of numerous pro-apoptotic molecules. The expression of Bcl-2 protein family members in different lines of human lung cancer cells became unregulated following the administration of extracts from Salvia milithoriza roots (Glc-82 cells) [ 149 ], Scutellaria baicalensis root (H358 and H2087 cells) [ 165 ], and Melissa officinalis leaves (A549) [ 166 ]. A similar result was observed for several human colon cancer cell lines treated with Coleus amboinicus leaves (WiDr cells) [ 167 ] and Vitex rotundifolia fruit (HCT-116, SW480, LoVo and HT-29 cells) extracts [ 146 ].…”

“…Increased expression of PARP1, a hallmark of apoptotic death, was observed in Glc-82 cells treated with Salvia miltiorrhiza roots extract [ 149 ], LNCaP cells incubated with Ocimum sanctum leaf extract [ 160 ], and PC-3 cells interacted with Nepeta cataria aerial part extract [ 172 ]. PARP activation was also demonstrated after the treatment of Teucrium mascatense whole plant extract in MCF-7 cells [ 156 ], Rosmarinus officinalis leaf extract in A549 cells [ 174 ], and Scutellaria baicalensis root extract in H358 and H2087 cells [ 165 ], suggesting the involvement of mitochondria in the apoptotic signals.…”

Gardenia jasminoides Enhances CDDP-Induced Apoptosis of Glioblastoma Cells via AKT/mTOR Pathway While Protecting Death of Astrocytes

“…Ratio of CDDP (µM) and GJ (µg/mL) was fixed to 1:250 and 1:500, and effect of four different combinations (1:250, 2:500, 1:500, 1:1000) was analyzed to determine the synergism between GJ and CDDP. Calculation formula for CI was as following [33]: Western blot assay was performed as described previously [32]. Briefly, samples were loaded (20 µg) and electrophoresis was carried out at 60 V throughout stacking gel and at 120 V afterwards.…”