A novel autophagy activator ginsenoside Rh2 enhances the efficacy of immunogenic chemotherapy.
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ABSTRACT:
SUBMITTER: Yang J
PROVIDER: S-EPMC9894730 | biostudies-literature | 2023 Feb
REPOSITORIES: biostudies-literature
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A novel autophagy activator ginsenoside Rh2 enhances the efficacy of immunogenic chemotherapy.
Yang Jing J Zhang Wei W Jia Lin L Shi Fei F Cao Min M Sun Jichao J Xu Chengchao C Li Zhijie Z Cheng Zhiqiang Z Zhao Shan-Chao SC Wang Jigang J Yang Chuanbin C
Clinical and translational medicine 20230201 2
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Project description:Immunogenic cell death (ICD) promotes the immune antitumor response via releasing damage-associated molecular patterns (DAMPs) from dying tumor cells. The induction of autophagy improves the efficacy of multiple immunogenic chemotherapies. Here, we show that piceatannol, a dietary phenolic compound that is widely distributed in multiple fruits and vegetables such as grapes, blueberries, and mushrooms, induces autophagy and enhances oxaliplatin (OXA)-induced anticancer immune response. Specifically, piceatannol enhanced OXA-induced release of DAMPs, several key hallmarks of ICD including ATP release, cell surface exposure of calreticulin, and high-mobility group box 1 (HMGB1) release. Mechanistically, piceatannol promoted autophagy via activating TFEB/TFE3, two key transcription factors of the autophagy-lysosome pathway, and inhibiting autophagy attenuated piceatannol plus OXA-induced ATP release. Furthermore, piceatannol induced endoplasmic reticulum stress, which is critical for its role in enhancing OXA-induced cell surface exposure of calreticulin, another key hallmark of ICD. Consistently, the combination of piceatannol with OXA promoted the anticancer effects in immunocompetent mice. Taken together, our results indicate the importance and great potential of dietary piceatannol in cancer immunotherapy. Therefore, piceatannol may be used as an ICD enhancer that improves the efficacy of chemotherapeutics such as OXA in cancer treatment with minimized toxicity.
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Project description:Hepatocellular carcinoma (HCC) is the most common liver cancer, with a very poor prognosis. There is an urgent need for an effective therapy for HCC. Ginsenoside Rh2 (GRh2) has been shown to significantly inhibit growth of some types of cancer, whereas its effects on HCC have not been examined. Here, we treated human HCC cells with different doses of GRh2, and found that GRh2 dose-dependently reduced HCC viability, in either CCK-8 assay or MTT assay. The effects of GRh2 on the cancer stem cells (CSCs)-like cells were determined by aldefluor flow cytometry and by tumor sphere formation, showing that GRh2 dose-dependently decreased the number of these CSCs-like cells in HCC. Autophagy-associated protein and β-catenin level were measured in GRh2-treated HCC cells by Western blot, showing that GRh2 increased autophagy and inhibited β-catenin signaling. Expression of short hairpin small interfering RNA (shRNA) for Atg7 in HCC cells completely abolished the effects of GRh2 on β-catenin and cell viability, while overexpression of β-catenin abolished the effects of GRh2 on autophagy and cell viability. Together, our data suggest that GRh2 may inhibit HCC cell growth, possibly through a coordinated autophagy and β-catenin signaling.
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Project description:BACKGROUND:Immunogenic cell death (ICD) is a peculiar modality of cellular demise that elicits adaptive immune responses and triggers T cell-dependent immunity. METHODS:Fluorescent biosensors were employed for an unbiased drug screen approach aiming at the identification of ICD enhancers. RESULTS:Here, we discovered thiostrepton as an enhancer of ICD able to boost chemotherapy-induced ATP release, calreticulin exposure and high-mobility group box 1 exodus. Moreover, thiostrepton enhanced anticancer immune responses of oxaliplatin (OXA) in vivo in immunocompetent mice, yet failed to do so in immunodeficient animals. Consistently, thiostrepton combined with OXA altered the ratio of cytotoxic T lymphocytes to regulatory T cells, thus overcoming immunosuppression and reinstating anticancer immunosurveillance. CONCLUSION:Altogether, these results indicate that thiostrepton can be advantageously combined with chemotherapy to enhance anticancer immunogenicity.
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Project description:BackgroundCancer cells through autophagy-mediated recycling to meet the metabolic demands of growth and proliferation. The steroidal saponin 20(S)-ginsenoside Rh2 effectively inhibits the growth and survival of a variety of tumor cell lines and animal models, but the effects of Rh2 on autophagy remain elusive.MethodsCell viability was measured by CCK-8 (cell counting kit-8) assays. Apoptosis, ROS generation and mitochondrial membrane potential were analyzed by flow cytometry. Western blot analyses were used to determine changes in protein levels. Morphology of apoptotic cells and autophagosome accumulation were analyzed by DAPI staining and transmission electron microscopy. Autophagy induction was monitored by acidic vesicular organelle staining, EGFP-LC3 and mRFP-GFP-LC3 transfection. Atg7 siRNA and autophagy regulator was used to assess the effect of autophagy on apoptosis induced by G-Rh2.ResultsIn this study, we found that low concentration G-Rh2 attenuated cancer cell growth and induced apoptosis upon serum-free starvation. Caspase 3 inhibitors failed to block apoptosis in G-Rh2-treated cells, indicating a caspase-independent mechanism. G-Rh2-treated cells in serum-deprived conditions showed impaired mitochondrial function, increased release and nuclear translocation of apoptosis-inducing factor, but little changes in the mitochondrial and cytoplasmic distributions of cytochrome C. Annexin A2 overexpression in 293T cells inhibited G-Rh2-induced apoptosis under serum-starved conditions. Meanwhile, G-Rh2 reduced lysosomal activity and inhibited the fusion of autophagosome and lysosome, leading to a block of autophagic flux. Knockdown Atg7 significantly inhibited autophagy and triggered AIF-induced apoptosis in serm free condition. The autophagy inducer significantly decreased the apoptosis levels of G-Rh2-treated cells in serum-free conditions.ConclusionsUnder nutrient deficient conditions, G-Rh2 represses autophagy in cervical cancer cells and enhanced apoptosis through an apoptosis-inducing factor mediated pathway.
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Project description:BackgroundGinsenoside Rh2 (G-Rh2) is a ginseng saponin that is widely investigated because of its remarkable antitumor activity. However, the molecular mechanism by which (20S) G-Rh2 triggers its functions and how target animals avoid its cytotoxic action remains largely unknown.MethodsPhage display was used to screen the human targets of (20S) G-Rh2. Fluorescence spectroscopy and UV-visible absorption spectroscopy were used to confirm the interaction of candidate target proteins and (20S) G-Rh2. Molecular docking was utilized to calculate the estimated free energy of binding and to structurally visualize their interactions. MTT assay and immunoblotting were used to assess whether human serum albumin (HSA), bovine serum albumin (BSA), and bovine serum can reduce the cytotoxic activity of (20S) G-Rh2 in HepG2 cells.ResultsIn phage display, (20S) G-Rh2-beads and (20R) G-Rh2-beads were combined with numerous kinds of phages, and a total of 111 different human complementary DNAs (cDNA) were identified, including HSA which had the highest rate. The binding constant and number of binding site in the interaction between (20S)-Rh2 and HSA were 3.5 × 105 M-1 and 1, and those in the interaction between (20S) G-Rh2 and BSA were 1.4 × 105 M-1 and 1. The quenching mechanism is static quenching. HSA, BSA and bovine serum significantly reduced the proapoptotic effect of (20S) G-Rh2.ConclusionHSA and BSA interact with (20S) G-Rh2. Serum inhibited the activity of (20S) G-Rh2 mainly due to the interaction between (20S) G-Rh2 and serum albumin (SA). This study proposes that HSA may enhance (20S) G-Rh2 water solubility, and thus might be used as nanoparticles in the (20S) G-Rh2 delivery process.
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Project description:Background20(S)-Ginsenoside Rh2 (GRh2) has been extensively studied for multifaceted health benefits. However, the anti-melanoma effect of GRh2 remains poorly understood. Herein, the anti-melanoma effects and underlying mechanisms of GRh2 were investigated.MethodsMTT assays, the EdU staining assay, flow cytometric analysis, the cellular thermal shift assay (CETSA), confocal microscope analysis, molecular docking, molecular dynamics (MD), immunoblotting, a B16F10 cell bearing mouse model were adopted to examine the anti-melanoma effect of mechanism of action of GRh2.ResultsIn melanoma cells, GRh2 was found to suppress cell proliferation, arrest cell cycle at G0/G1 phase and evoke apoptosis. GRh2 initiated autophagy and inhibited the activity of mTOR, the autophagy negative regulator, in melanoma cells. Repressing autophagy enhanced the anti-melanoma efficacy of GRh2. Molecular docking, MD and CETSA studies revealed that GRh2 stably bound to Src protein (one of the upstream kinases of STAT3). GRh2 suppressed Src and STAT3 activities, thereof prohibiting STAT3 nuclear translocation in melanoma cells. STAT3 over-activation attenuated the cytotoxic, apoptotic and autophagy inductive effects of GRh2. Additionally, GRh2 suppressed B16F10 tumor growth without inducing obvious toxicity in mice. It downregulated phospho-Src, phospho-STAT3, phospho-mTOR and Mcl-1 protein levels, while elevated cleaved-PARP and LC3B-II protein levels in B16F10 tumors.ConclusionGRh2 exerts anti-melanoma effects through suppressing Src/STAT3 signaling. This study advances our understanding on the anti-melanoma mechanism of GRh2 and indicates that the intake of GRh2 has the potential to retard melanoma progression.
| S-EPMC11583474 | biostudies-literature
Project description:Ginsenoside Rh2 increases the efficacy of doxorubicin (DOX) treatment in murine models of solid and ascites Ehrlich's adenocarcinoma. In a solid tumor model (treatment commencing 7 days after inoculation), DOX + Rh2 co-treatment was significantly more efficacious than DOX alone. If treatment was started 24 h after inoculation, the inhibition of tumor growth of a solid tumor for the DOX + Rh2 co-treatment group was complete. Furthermore, survival in the ascites model was dramatically higher for the DOX + Rh2 co-treatment group than for DOX alone. Mechanisms underlying the combined DOX and Rh2 effects were studied in primary Ehrlich's adenocarcinoma-derived cells and healthy mice's splenocytes. Despite the previously established Rh2 pro-oxidant activity, DOX + Rh2 co-treatment revealed no increase in ROS compared to DOX treatment alone. However, DOX + Rh2 treatment was more effective in suppressing Ehrlich adenocarcinoma cell adhesion than either treatment alone. We hypothesize that the benefits of DOX + Rh2 combination treatment are due to the suppression of tumor cell attachment/invasion that might be effective in preventing metastatic spread of tumor cells. Ginsenoside Rh2 was found to be a modest activator in a Neh2-luc reporter assay, suggesting that Rh2 can activate the Nrf2-driven antioxidant program. Rh2-induced direct activation of Nrf2 might provide additional benefits by minimizing DOX toxicity towards non-cancerous cells.
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Project description:A number of natural plant products have a long-standing history in both traditional and modern medical applications. Some secondary metabolites induce autophagy and mediate autophagy-dependent healthspan- and lifespan-extending effects in suitable mouse models. Here, we identified isobacachalcone (ISO) as a non-toxic inducer of autophagic flux that acts on human and mouse cells in vitro, as well as mouse organs in vivo. Mechanistically, ISO inhibits AKT as well as, downstream of AKT, the mechanistic target of rapamycin complex 1 (mTORC1), coupled to the activation of the pro-autophagic transcription factors EB (TFEB) and E3 (TFE3). Cells equipped with a constitutively active AKT mutant failed to activate autophagy. ISO also stimulated the AKT-repressible activation of all three arms of the unfolded stress response (UPR), including the PERK-dependent phosphorylation of eukaryotic initiation factor 2α (eIF2α). Knockout of TFEB and/or TFE3 blunted the UPR, while knockout of PERK or replacement of eIF2α by a non-phosphorylable mutant reduced TFEB/TFE3 activation and autophagy induced by ISO. This points to crosstalk between the UPR and autophagy. Of note, the administration of ISO to mice improved the efficacy of immunogenic anticancer chemotherapy. This effect relied on an improved T lymphocyte-dependent anticancer immune response and was lost upon constitutive AKT activation in, or deletion of the essential autophagy gene Atg5 from, the malignant cells. In conclusion, ISO is a bioavailable autophagy inducer that warrants further preclinical characterization.
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Project description:Liver cancer is one of the leading causes of malignancy-associated mortality worldwide and its clinical therapy remains very challenging. Ginsenoside Rh2 (Rh2) has been reported to have antitumor effects on some types of cancer, including liver cancer. However, its regulatory mechanism has not been extensively evaluated. In the present study, Rh2 increased the expression of microRNA (miR)-200b-5p, miR-224-3p and miR-146a-5p, and decreased the expression of miR-26b-3p and miR-29a-5p. Of the three upregulated miRs, miR-146a-5p exhibited the highest fold elevation. In accordance with a previous study, Rh2 effectively inhibited the survival of liver cancer cells in vitro and in a mouse model. In addition, it was observed that Rh2 markedly promoted liver cancer apoptosis and inhibited colony formation. Cell apoptosis and the inhibition of cell survival as well as colony formation induced by Rh2 were enhanced and weakened by miR-146a-5p overexpression and inhibition, respectively. The results of the present study provide further evidence of the antitumor effect of Rh2 in liver cancer and also demonstrate that this effect may be mediated via the regulation of miR-146a-5p expression in the liver cancer cell line HepG2. The results indicated that miR-146a-5p may be a promising regulatory factor in Rh2-mediated effects in liver cancer.
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Project description:BackgroundT-cell acute lymphoblastic leukemia (T-ALL) is a kind of aggressive hematological cancer, and the PI3K/Akt/mTOR signaling pathway is activated in most patients with T-ALL and responsible for poor prognosis. 20(S)-Ginsenoside Rh2 (20(S)-GRh2) is a major active compound extracted from ginseng, which exhibits anti-cancer effects. However, the underlying anticancer mechanisms of 20(S)-GRh2 targeting the PI3K/Akt/mTOR pathway in T-ALL have not been explored.MethodsCell growth and cell cycle were determined to investigate the effect of 20(S)-GRh2 on ALL cells. PI3K/Akt/mTOR pathway-related proteins were detected in 20(S)-GRh2-treated Jurkat cells by immunoblotting. Antitumor effect of 20(S)-GRh2 against T-ALL was investigated in xenograft mice. The mechanisms of 20(S)-GRh2 against T-ALL were examined by cell proliferation, apoptosis, and autophagy.ResultsIn the present study, the results showed that 20(S)-GRh2 decreased cell growth and arrested cell cycle at the G1 phase in ALL cells. 20(S)-GRh2 induced apoptosis through enhancing reactive oxygen species generation and upregulating apoptosis-related proteins. 20(S)-GRh2 significantly elevated the levels of pEGFP-LC3 and autophagy-related proteins in Jurkat cells. Furthermore, the PI3K/Akt/mTOR signaling pathway was effectively blocked by 20(S)-GRh2. 20(S)-GRh2 suppressed cell proliferation and promoted apoptosis and autophagy by suppressing the PI3K/Akt/mTOR pathway in Jurkat cells. Finally, 20(S)-GRh2 alleviated symptoms of leukemia and reduced the number of white blood cells and CD3 staining in the spleen of xenograft mice, indicating antitumor effects against T-ALL in vivo.ConclusionThese findings indicate that 20(S)-GRh2 exhibits beneficial effects against T-ALL through the PI3K/Akt/mTOR pathway and could be a natural product of novel target for T-ALL therapy.
| S-EPMC7471214 | biostudies-literature