The multifaceted mechanisms of Dihydrotanshinone I in the treatment of tumors

The morbidity and mortality of malignant tumors are progressively rising on an annual basis. Traditional Chinese Medicine (TCM) holds promise as a possible therapeutic agent for the avoidance or therapy of malignant tumors. Salvia miltiorrhiza Bunge (Danshen), a traditional Asian functional food, has therapeutic characteristics in application for the treatment of malignant tumors. Dihydrotanshinone I (DHTS) is the principal lipophilic phenanthraquinone compound found in Salvia miltiorrhiza Bunge, whose anti-tumor effect has attracted widespread attention. The anti-tumor effects include inhibiting cancer cell proliferation, triggering apoptosis of tumor cells, inducing ferroptosis in tumor cells, inhibiting tumor cell invasion and metastasis, and improving drug resistance of tumor cells. In this paper, we summarized and analyzed the mechanisms and targets of anti-tumor effect of DHTS, providing new ideas and establishing a solid theoretical basis for the future advancement and clinical treatment of DHTS.

Dihydrotanshinone I inhibits gallbladder cancer growth by targeting the Keap1-Nrf2 signaling pathway and Nrf2 phosphorylation

BACKGROUND

Gallbladder cancer (GBC) poses a significant risk to human health. Its development is influenced by numerous factors, particularly the homeostasis of reactive oxygen species (ROS) within cells. This homeostasis is crucial for tumor cell survival, and abnormal regulation of ROS is associated with the occurrence and progression of many cancers. Dihydrotanshinone I (DHT I), a biologically effective ingredient isolated from Salvia miltiorrhiza, has exhibited cytotoxic properties against various tumor cells by inducing apoptosis. However, the precise molecular mechanisms by which dht I exerts its cytotoxic effects remain unclear.

PURPOSE

To explore the anti-tumor impact of dht I on GBC and elucidate the potential molecular mechanisms.

METHODS

The proliferation of GBC cells, NOZ and SGC-996, was assessed using various assays, including CCK-8 assay, colony formation assay and EdU staining. We also examined cell apoptosis, cell cycle progression, ROS levels, and alterations in mitochondrial membrane potential to delve into the intricate molecular mechanism. Quantitative PCR (qPCR), immunofluorescence staining, and Western blotting were performed to evaluate target gene expression at both the mRNA and protein levels. The correlation between nuclear factor erythroid 2-related factor 2 (Nrf2) and kelch-like ECH-associated protein 1 (Keap1) were examined using co-immunoprecipitation. Finally, the in vivo effect of dht I was investigated using a xenograft model of gallbladder cancer in mice.

RESULTS

Our research findings indicated that dht I exerted cytotoxic effects on GBC cells, including inhibiting proliferation, disrupting mitochondrial membrane potential, inducing oxidative stress and apoptosis. Our in vivo studies substantiated the inhibition of dht I on tumor growth in xenograft nude mice. Mechanistically, dht I primarily targeted Nrf2 by promoting Keap1 mediated Nrf2 degradation and inhibiting protein kinase C (PKC) induced Nrf2 phosphorylation. This leads to the suppression of Nrf2 nuclear translocation and reduction of its target gene expression. Moreover, Nrf2 overexpression effectively counteracted the anti-tumor effects of dht I, while Nrf2 knockdown significantly enhanced the inhibitory effect of dht I on GBC. Meanwhile, PKC inhibitors and nuclear import inhibitors increased the sensitivity of GBC cells to dht I treatment. Conversely, Nrf2 activators, proteasome inhibitors, antioxidants and PKC activators all antagonized dht I induced apoptosis and ROS generation in NOZ and SGC-996 cells.

CONCLUSION

Our findings indicated that dht I inhibited the growth of GBC cells by regulating the Keap1-Nrf2 signaling pathway and Nrf2 phosphorylation. These insights provide a strong rationale for further investigation of dht I as a potential therapeutic agent for GBC treatment.

Dihydrotanshinone I reduces H9c2 cell damage by regulating AKT and MAPK signaling pathways

Cardiovascular disease is the deadliest disease in the world. Previous studies have shown that Dihydrotanshinone I (DHT) can improve cardiac function after myocardial injury. This study aimed to observe the protective effect and mechanism of DHT on H9c2 cells by establishing an oxygen-glucose deprivation/reoxygenation (OGD/R) injury model. By constructing OGD/R injury simulation of H9c2 cells in a myocardial injury model, the proliferation of H9c2 cells treated with DHT concentrations of 0.1 μmol/L were not affected at 24, 48, and 72 h. DHT can significantly reduce the apoptosis of H9c2 cells caused by OGD/R. Compared with the OGD/R group, DHT treatment significantly reduced the level of MDA and increased the level of SOD in cells. DHT treatment of cells can significantly reduce the levels of ROS and Superoxide in mitochondria in H9c2 cells caused by OGD/R and H2O2. DHT significantly reduced the phosphorylation levels of P38MAPK and ERK in H9c2 cells induced by OGD/R, and significantly increased the phosphorylation levels of AKT in H9c2 cells. DHT can significantly reduce the oxidative stress damage of H9c2 cells caused by H2O2 and OGD/R, thereby reducing the apoptosis of H9c2 cells. And this may be related to regulating the phosphorylation levels of AKT, ERK, and P38MAPK.

Dihydrotanshinone I attenuates estrogen-deficiency bone loss through RANKL-stimulated NF-κB, ERK and NFATc1 signaling pathways

Postmenopausal osteoporosis, a chronic condition that predominantly affects postmenopausal women, presents a significant impediment to their overall well-being. The condition arises from estrogen deficiency, leading to enhanced osteoclast activity. Salvia miltiorrhiza, a well-established Chinese herbal medicine with a history of clinical use for osteoporosis treatment, contains diverse active constituents that have shown inhibitory effects on osteoclast formation and bone loss. Dihydrotanshinone I (DTI), a phenanthrenonequinone compound derived from the root of Salvia miltiorrhiza, has been identified as a potential therapeutic agent, although its mechanism of action on osteoclasts remains elusive. In this study, we aimed to elucidate the inhibitory potential of DTI on RANKL-induced osteoclastogenesis. We observed the ability of DTI to effectively impede the expression of key osteoclast-specific genes and proteins, as assessed by Real-time PCR and Western Blotting analyses. Mechanistically, DTI exerted its inhibitory effects on osteoclast formation by modulating critical signaling pathways including NF-κB, ERK, and calcium ion signaling. Notably, DTI intervention disrupted the nuclear translocation and subsequent transcriptional activity of the NFATc1, thus providing mechanistic insights into its inhibitory role in osteoclastogenesis. To further assess the therapeutic potential of DTI, we employed an ovariectomized osteoporosis animal model to examine its impact on bone loss. Encouragingly, DTI demonstrated efficacy in mitigating bone loss induced by estrogen deficiency. In conclusion, our investigation elucidates the ability of DTI to regulate multiple signaling pathways activated by RANKL, leading to the inhibition of osteoclast formation and prevention of estrogen-deficiency osteoporosis. Consequently, DTI emerges as a promising candidate for the treatment of osteoporosis.

Biotransformation of triterpenoid ganoderic acids from exogenous diterpene dihydrotanshinone I in the cultures of Ganoderma sessile

BACKGROUND

Triterpenoids have shown a wide range of biological activities including antitumor and antiviral effects. Typically, triterpenes are synthesized through the mevalonate pathway and are extracted from natural plants and fungi. In this work, triterpenoids, ganoderic acids (GAs) were discovered to be produced via biotransformation of a diterpene, 15,16-dihydrotanshinone I (DHT) in the liquid cultured Ganoderma sessile mycelium.

RESULTS

Firstly, the biotransformation products, two rare GAs were isolated and purified by column chromatography, and characterized using HR-ESI-MS spectrometry and NMR spectrometry. The two compounds were Lanosta-7,9(11),24-trien-15α,22,β-diacetoxy-3β-hydroxy-26-oic acid (LTHA) and Lanosta-7,9(11),24-trien-15α,22,β-diacetoxy-3β-carbonyl-26-oic acid (LTCA). Then, transcriptome and proteome technologies were employed to measure the expression of mRNA and protein, which further confirmed that triterpenoid GAs could be transformed from exogenous diterpenoid DHT. At the molecular level, we proposed a hypothesis of the mechanism by which DHT converted to GAs in G. sessile mycelium, and the possible genes involved in biotransformation were verified by RT-qPCR.

CONCLUSIONS

Two rare GAs were obtained and characterized. A biosynthetic pathway of GAs from DHT was proposed. Although the synthetic route was not confirmed, this study provided important insights into omics resources and candidate genes for studying the biotransformation of diterpenes into triterpenes.

Integrated proteomics and phosphoproteomics profiling reveals the cardioprotective mechanism of bioactive compounds derived from Salvia miltiorrhiza Burge

BACKGROUND

Natural products are an important source for discovering novel drugs due to their various pharmacological activities. Salvia miltiorrhiza Burge (Danshen) has been shown to have promising therapeutic potential in the management of heart diseases, making it a candidate for cardiovascular drug discovery. Currently, there is limited quantitative analysis of the phosphorylation levels of Danshen-derived natural products on a proteome-wide, which may bias the study of their mechanisms of action.

PURPOSE

This study aimed to evaluate the global signaling perturbation induced by Danshen-derived bioactive compounds and their potential relationship with myocardial ischemia/reperfusion (IR) injury therapy.

STUDY DESIGN

We employed quantitative proteome and phosphoproteome analysis to identify dysregulated signaling in IR injury hearts from mice. We compared changes induced by Danshen-derived compounds based on IR-associated phospho-events, using an integrative approach that maps relative abundance of proteins and phosphorylation sites.

METHODS

Isobaric chemical tandem mass tags (TMT) labeled multiplexing strategy was used to generate unbiased quantitative proteomics and phosphoproteomics data. Highly accurate and precise TMT quantitation was performed using the Orbitrap Fusion Tribrid Mass Spectrometer with synchronous precursor selection MS3 detection mode. Mass spectrometric raw files were analyzed with MaxQuant (2.0.1.0) and statistical and bioinformatics analysis was conducted with Perseus (1.6.15).

RESULTS

We quantified 3661 proteins and over 11,000 phosphosites in impaired heart tissue of the IR mice model, expanding our knowledge of signaling pathways and other biological processes disrupted in IR injury. Next, 1548 and 5545 differently expressed proteins and phosphosites were identified by quantifying the proteome and phosphoproteome of H9c2 cells treated by five Danshen bioactive compounds respectively. Results revealed the vast differences in abilities of five Danshen-derived bioactive compounds to regulate phosphorylation modifications in cardiomyocytes, with dihydrotanshinone I (DHT) showing potential for protecting against IR injury by modulating the AMPK/mTOR signaling pathway.

CONCLUSIONS

This study provides a new strategy for analyzing drug/natural product-regulated phosphorylation modification levels on a proteome-wide scale, leading to a better understanding of cell signaling pathways and downstream phenotypic responses.

Dihydrotanshinone I inhibits hepatocellular carcinoma cells proliferation through DNA damage and EGFR pathway

Background

The incidence and mortality of hepatocellular carcinoma (HCC) are globally on the rise. Dihydrotanshinone I, a natural product isolated from Salvia miltiorrhiza Bunge, has attracted extensive attention in recent years for its anti-tumour proliferation efficiency.

Methods

Cell proliferations in hepatoma cells (Huh-7 and HepG2) were evaluated by MTT and colony formation assays. Immunofluorescence (IF) of 53BP1 and flow cytometry analysis were performed to detect DNA damage and cell apoptosis. Furthermore, network pharmacological analysis was applied to explore the potential therapeutic targets and pathway of dihydrotanshinone I.

Results

The results showed that dihydrotanshinone I effectively inhibited the proliferation of Huh-7 and HepG2 cells. Moreover, dihydrotanshinone I dose-dependently induced DNA-damage and apoptosis in vitro. Network pharmacological analysis and molecular simulation results indicated that EGFR might be a potential therapeutic target of dihydrotanshinone I in HCC. Collectively, our findings suggested that dihydrotanshinone I is a novel candidate therapeutic agent for HCC treatment.

Dihydrotanshinone I preconditions myocardium against ischemic injury via PKM2 glutathionylation sensitive to ROS

Ischemic preconditioning (IPC) is a potential intervention known to protect the heart against ischemia/reperfusion injury, but its role in the no-reflow phenomenon that follows reperfusion is unclear. Dihydrotanshinone I (DT) is a natural compound and this study illustrates its role in cardiac ischemic injury from the aspect of IPC. Pretreatment with DT induced modest ROS production and protected cardiomyocytes against oxygen and glucose deprivation (OGD), but the protection was prevented by a ROS scavenger. In addition, DT administration protected the heart against isoprenaline challenge. Mechanistically, PKM2 reacted to transient ROS via oxidization at Cys423/Cys424, leading to glutathionylation and nuclear translocation in dimer form. In the nucleus, PKM2 served as a co-factor to promote HIF-1α-dependent gene induction, contributing to adaptive responses. In mice subjected to permanent coronary ligation, cardiac-specific knockdown of Pkm2 blocked DT-mediated preconditioning protection, which was rescued by overexpression of wild-type Pkm2, rather than Cys423/424-mutated Pkm2. In conclusion, PKM2 is sensitive to oxidation, and subsequent glutathionylation promotes its nuclear translocation. Although IPC has been viewed as a protective means against reperfusion injury, our study reveals its potential role in protection of the heart from no-reflow ischemia.

Dihydrotanshinone I Inhibits the Proliferation and Growth of Oxaliplatin-Resistant Human HCT116 Colorectal Cancer Cells

Oxaliplatin (OXA) is a first-line chemotherapeutic drug for the treatment of colorectal cancer (CRC), but acquired drug resistance becomes the main cause of treatment failure. Increasing evidence has shown that some natural components may serve as chemoresistant sensitizers. In this study, we discovered Dihydrotanshinone I (DHTS) through virtual screening using a ligand-based method, and explored its inhibitory effects and the mechanism on OXA-resistant CRC in vitro and in vivo. The results showed that DHTS could effectively inhibit the proliferation of HCT116 and HCT116/OXA resistant cells. DHTS-induced cell apoptosis blocked cell cycle in S and G₂/M phases, and enhanced DNA damage of HCT116/OXA cells in a concentration-dependent manner. DHTS also exhibited the obvious inhibition of tumor growth in the HCT116/OXA xenograft model. Mechanistically, DHTS could downregulate the expression of Src homology 2 structural domain protein tyrosine phosphatase (SHP2) and Wnt/β-catenin, as well as conventional drug resistance and apoptosis-related proteins such as multidrug resistance associated proteins (MRP1), P-glycoprotein (P-gp), Bcl-2, and Bcl-xL. Thus, DHTS markedly induces cell apoptosis and inhibits tumor growth in OXA-resistant HCT116 CRC mice models, which can be used as a novel lead compound against OXA-resistant CRC.

Dihydrotanshinone I inhibits ovarian tumor growth by activating oxidative stress through Keap1-mediated Nrf2 ubiquitination degradation

Dihydrotanshinone I (DHT), a bioactive compound in Salvia miltiorrhiza, was reported to exhibit cytotoxicity against various malignancies. However, the underlying mechanism on ovarian cancer remains unclear. Here, DHT inhibited cell viability of ovarian cancer HO8910PM, SKOV3, A2780 and ES2 cells. It showed moderate inhibitory effect on ovarian epithelial IOSE80 cells and lower toxicity than chemotherapy drugs. DHT induced apoptosis and G2 cell cycle arrest accompanied by reduced expression of Bcl-2, Caspase-3, and increased Bax. Meanwhile, DHT increased ROS accumulation, decreased mitochondrial membrane potential and activated oxidative stress in HO8910PM and ES2 cells. Mechanistically, DHT inhibited Nrf2 and p62 expression, Nrf2 target genes and enzymes, and Nrf2 nuclear translocation, while increased the expression of Nrf2 inhibitor Keap1. NAC, a ROS scavenger, rescued DHT-induced proliferation inhibition, ROS generation and Nrf2 inhibition. DHT alleviated tBHQ-induced Nrf2 expression and increased its mRNA level. However, the proteasome inhibitor MG132 blocked DHT-induced Nrf2 inhibition, suggesting a post-translational regulation manner. DHT enhanced Nrf2 binding with Keap1, leading to potentiated Nrf2 ubiquitination degradation. Furthermore, Nrf2 and p62 overexpression blocked DHT-induced Nrf2 and p62 inhibition. Consistent with the in vitro results, DHT significantly delayed tumor growth in HO8910PM and ES2 xenograft nude mice, decreased tumor marker HE4 and CA125 levels, reversed the abnormally expressed proteins including Ki67, Nrf2, p62, Keap1, Bcl-2, CyclinB1, Cdc-2, and antioxidant enzymes SOD, CAT in vivo. Serum from DHT-treated mice also inhibited cell growth in vitro. Taken together, DHT exhibits anti-ovarian tumor effect by activating oxidative stress through ubiquitination-mediated Nrf2 degradation. Our findings implicate a potential application of DHT for ovarian cancer therapy.

Dihydrotanshinone I inhibits the growth of hepatoma cells by direct inhibition of Src

BACKGROUND

Liver cancer is one of the leading causes of cancer-related death worldwide. Dihydrotanshinone I (DHI) was shown to inhibit the growth of several types of cancer. However, research related to hepatoma treatment using DHI is limited.

PURPOSE

Here, we explored the inhibitory effect of DHI on the growth of hepatoma cells, and investigated the underlying molecular mechanisms.

METHODS

The proliferation of Hep3B, SMCC-7721 and SK-Hep1 hepatoma cells was evaluated using the MTS and Edu staining assay. Hepatoma cell death was analyzed with a LIVE/DEAD Cell Imaging Kit. The relative expression and phosphorylation of proto-oncogene tyrosine-protein kinase Src (Src) and signal transducer and activator of transcription-3 (STAT3) proteins in hepatoma cells, as well as the expression of other protein components, were measured by western blotting. The structural interaction of DHI with Src proteins was evaluated by molecular docking, molecular dynamics simulation, surface plasmon resonance imaging and Src kinase inhibition assay. Src overexpression was achieved by infection with an adenovirus vector encoding human Src. Subsequently, the effects of DHI on tumor growth inhibition were further validated using mouse xenograft models of hepatoma.

RESULTS

In vitro studies showed that treatment with DHI inhibited the proliferation and promoted cell death of Hep3B, SMCC-7721 and SK-Hep1 hepatoma cells. We further identified and verified Src as a direct target of DHI by using molecular stimulation, surface plasmon resonance image and Src kinase inhibition assay. Treatment with DHI reduced the in vitro phosphorylation levels of Src and STAT3, a transcription factor regulated by Src. In the xenograft mouse models, DHI dose-dependently suppressed tumor growth and Src and STAT3 phosphorylation. Moreover, Src overexpression partly abrogated the inhibitory effects of DHI on the proliferation and cell death in hepatoma cells.

CONCLUSION

Our results suggest that DHI inhibits the growth of hepatoma cells by direct inhibition of Src.

STAT3-mediated activation of mitochondrial pathway contributes to antitumor effect of dihydrotanshinone I in esophageal squamous cell carcinoma cells

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies with a poor prognosis, and its treatment remains a great challenge. Dihydrotanshinone I (DHTS) has been reported to exert antitumor effect in many cancers. However, the role of DHTS in ESCC remains unclear.

AIM

To investigate the antitumor effect of DHTS in ESCC and the underlying mechanisms.

METHODS

CCK-8 assay and cell cycle analysis were used to detect proliferation and cell cycle in ESCC cells. Annexin V-PE/7-AAD double staining assay and Hoechst 33258 staining were used to detect apoptosis in ESCC cells. Western blot was used to detect the expression of proteins associated with the mitochondrial pathway. Immunofluorescence was used to detect the expression of phosphorylated STAT3 (pSTAT3) in DHTS-treated ESCC cells. ESCC cells with STAT3 knockdown and overexpression were constructed to verify the role of STAT3 in DHTS induced apoptosis. A xenograft tumor model in nude mice was used to evaluate the antitumor effect of DHTS in vivo.

RESULTS

After treatment with DHTS, the proliferation of ESCC cells was inhibited in a dose- and time-dependent manner. Moreover, DHTS induced cell cycle arrest in the G0/1 phase. Annexin V-PE/7-AAD double staining assay and Hoechst 33258 staining revealed that DHTS induced obvious apoptosis in KYSE30 and Eca109 cells. At the molecular level, DHTS treatment reduced the expression of pSTAT3 and anti-apoptotic proteins, while increasing the expression of pro-apoptotic proteins in ESCC cells. STAT3 knockdown in ESCC cells markedly promoted the activation of the mitochondrial pathway while STAT3 overexpression blocked the activation of the mitochondrial pathway. Additionally, DHTS inhibited tumor cell proliferation and induced apoptosis in a xenograft tumor mouse model.

CONCLUSION

DHTS exerts antitumor effect in ESCC via STAT3-mediated activation of the mitochondrial pathway. DHTS may be a novel therapeutic agent for ESCC.

Tanshinones inhibit NLRP3 inflammasome activation by alleviating mitochondrial damage to protect against septic and gouty inflammation

Tanshinones, the active ingredients derived from the roots of Salvia miltiorrhiza, have been widely used as traditional medicinal herbs for treating human diseases. Although tanshinones showed anti-inflammatory effects in many studies, large knowledge gaps remain regarding their underlying mechanisms. Here, we identified 15 tanshinones that suppressed the activation of NLRP3 inflammasome and studied their structure-activity relationships. Three tanshinones (tanshinone IIA, isocryptotanshinone, and dihydrotanshinone I) reduced mitochondrial reactive-oxygen species production in lipopolysaccharide (LPS)/nigericin-stimulated macrophages and correlated with altered mitochondrial membrane potentials, mitochondria complexes activities, and adenosine triphosphate and protonated-nicotinamide adenine dinucleotide production. The tanshinones may confer mitochondrial protection by promoting autophagy and the AMP-activated protein kinase pathway. Importantly, our findings demonstrate that dihydrotanshinone I improved the survival of mice with LPS shock and ameliorated inflammatory responses in septic and gouty animals. Our results suggest a potential pharmacological mechanism whereby tanshinones can effectively treat inflammatory diseases, such as septic and gouty inflammation.

Identification of dihydrotanshinone I as an ERp57 inhibitor with anti-breast cancer properties via the UPR pathway

Salvia miltiorrhiza (Danshen) is a well-known traditional Chinese medicine for treating various diseases, such as breast cancer. However, knowledge regarding its mechanisms is scant. Herein, the active ingredient dihydrotanshinone I (DHT) in Salvia miltiorrhiza extract (SME), which binds ERp57 was identified and verified by an enzymatic solid-phase method combined with LC-MS/MS. DHT potentially inhibited ERp57 activity and suppressed ERp57 expression at both the RNA and protein levels. Molecular docking simulation indicated that DHT could form a hydrogen bond with catalytic site of ERp57. Moreover, ERp57 overexpression decreased DHT-induced cytotoxicity in MDA-MB-231 cells. Thereafter, the signaling pathway downstream of ERp57 was investigated by Western blot analysis. The mechanistic study revealed that DHT treatment resulted in activation of endoplasmic reticulum (ER) stress, the unfolded protein response (UPR), and cellular apoptosis. In conclusion, our data implied that DHT targeted ERp57 for inhibition and induced ER stress and UPR activation, which in turn triggered breast cancer cell apoptosis.

Activated PKB/GSK-3β synergizes with PKC-δ signaling in attenuating myocardial ischemia/reperfusion injury via potentiation of NRF2 activity: Therapeutic efficacy of dihydrotanshinone-I

Disrupted redox status primarily contributes to myocardial ischemia/reperfusion injury (MIRI). NRF2, the endogenous antioxidant regulator, might provide therapeutic benefits. Dihydrotanshinone-I (DT) is an active component in Salvia miltiorrhiza with NRF2 induction potency. This study seeks to validate functional links between NRF2 and cardioprotection of DT and to investigate the molecular mechanism particularly emphasizing on NRF2 cytoplasmic/nuclear translocation. DT potently induced NRF2 nuclear accumulation, ameliorating post-reperfusion injuries via redox alterations. Abrogated cardioprotection in NRF2-deficient mice and cardiomyocytes strongly supports NRF2-dependent cardioprotection of DT. Mechanistically, DT phosphorylated NRF2 at Ser40, rendering its nuclear-import by dissociating from KEAP1 and inhibiting degradation. Importantly, we identified PKC-δ-(Thr505) phosphorylation as primary upstream event triggering NRF2-(Ser40) phosphorylation. Knockdown of PKC-δ dramatically retained NRF2 in cytoplasm, convincing its pivotal role in mediating NRF2 nuclear-import. NRF2 activity was further enhanced by activated PKB/GSK-3β signaling via nuclear-export signal blockage independent of PKC-δ activation. By demonstrating independent modulation of PKC-δ and PKB/GSK-3β/Fyn signaling, we highlight the ability of DT to exploit both nuclear import and export regulation of NRF2 in treating reperfusion injury harboring redox homeostasis alterations. Coactivation of PKC and PKB phenocopied cardioprotection of DT in vitro and in vivo, further supporting the potential applicability of this rationale.

TFEB-NF-κB inflammatory signaling axis: a novel therapeutic pathway of Dihydrotanshinone I in doxorubicin-induced cardiotoxicity

BACKGROUND

Doxorubicin is effective in a variety of solid and hematological malignancies. Unfortunately, clinical application of doxorubicin is limited due to a cumulative dose-dependent cardiotoxicity. Dihydrotanshinone I (DHT) is a natural product from Salvia miltiorrhiza Bunge with multiple anti-tumor activity and anti-inflammation effects. However, its anti-doxorubicin-induced cardiotoxicity (DIC) effect, either in vivo or in vitro, has not been elucidated yet. This study aims to explore the anti-inflammation effects of DHT against DIC, and to elucidate the potential regulatory mechanism.

METHODS

Effects of DHT on DIC were assessed in zebrafish, C57BL/6 mice and H9C2 cardiomyocytes. Echocardiography, histological examination, flow cytometry, immunochemistry and immunofluorescence were utilized to evaluate cardio-protective effects and anti-inflammation effects. mTOR agonist and lentivirus vector carrying GFP-TFEB were applied to explore the regulatory signaling pathway.

RESULTS

DHT improved cardiac function via inhibiting the activation of M1 macrophages and the excessive release of pro-inflammatory cytokines both in vivo and in vitro. The activation and nuclear localization of NF-κB were suppressed by DHT, and the effect was abolished by mTOR agonist with concomitant reduced expression of nuclear TFEB. Furthermore, reduced expression of nuclear TFEB is accompanied by up-regulated phosphorylation of IKKα/β and NF-κB, while TFEB overexpression reversed these changes. Intriguingly, DHT could upregulate nuclear expression of TFEB and reduce expressions of p-IKKα/β and p-NF-κB.

CONCLUSIONS

Our results demonstrated that DHT can be applied as a novel cardioprotective compound in the anti-inflammation management of DIC via mTOR-TFEB-NF-κB signaling pathway. The current study implicates TFEB-IKK-NF-κB signaling axis as a previously undescribed, druggable pathway for DIC.

Metabolic reprogramming in colon cancer reversed by DHTS through regulating PTEN/AKT/HIF1α mediated signal pathway

BACKGROUND

Metabolic reprogramming and hypoxia contribute to the resistance of conventional chemotherapeutic drugs in kinds of cancers. In this study, we investigated the effect of dihydrotanshinone I (DHTS) on reversing dysregulated metabolism of glucose and fatty acid in colon cancer and elucidated its mechanism of action.

METHODS

Cell viability was determined by MTT assay. Oxidative phosphorylation, glycolysis, and mitochondrial fuel oxidation were assessed by Mito stress test, glycolysis stress test, and mito fuel flex test, respectively. Anti-cancer activity of DHTS in vivo was evaluated in Colon cancer xenograft. Hexokinase activity and free fatty acid (FFA) content were assessed using respective Commercial kits. Gene expression patterns were determined by performing DNA microarray analysis and real-time PCR. Protein expression was assessed using immunoblotting and immunohistochemistry.

RESULTS

DHTS showed similar cytotoxicity against colon cancer cells under hypoxia and normoxia. DHTS decreased the efficiency of glucose and FA as mitochondrial fuels in HCT116 cells, which efficiently reversed by VO-OHpic trihydrate. DHTS reduced hexokinase activity and free fatty acid (FFA) content in tumor tissue of xenograft model of colon cancer. Gene expression patterns in metabolic pathways were dramatically differential between model and treatment group. Increases in PTEN and a substantial decrease in the expression of SIRT3, HIF1α, p-AKT, HKII, p-MTOR, RHEB, and p-ACC were detected.

CONCLUSIONS

DHTS reversed metabolic reprogramming in colon cancer through PTEN/AKT/HIF1α-mediated signal pathway.

GENERAL SIGNIFICANCE

The study is the first to report the reverse of metabolic reprogramming by DHTS in colon cancer. Meantime, SIRT3/PTEN/AKT/HIF1α mediated signal pathway plays a critical role during this process.

Dihydrotanshinone I induced apoptosis and autophagy through caspase dependent pathway in colon cancer

BACKGROUND

Dihydrotanshinone I (DHTS) was previously reported to exhibit the most potent anti-cancer activity among several tanshinones in colon cancer cells. Its cytotoxic action was reactive oxygen species (ROS) dependent but p53 independent.

PURPOSE

To further study the anti-cancer activity of DHTS and its molecular mechanisms of action in colon cancer both in vitro and in vivo.

METHODS

Caspase activity was detected by fluorescence assay. Apoptosis was detected by flow cytometry and TUNEL assay. Protein levels were analyzed by western blotting. Knockdown of target gene was achieved by siRNA transfection. Formation of LC3B puncta and activation of caspase-3 were detected by confocal fluorescence microscope. In vivo anti-colon cancer activity of DHTS was observed in xenograft tumors in NOD/SCID mice.

RESULTS

Anti-colon cancer activity of DHTS by inducing apoptosis and autophagy was observed both in vitro and in vivo. Mitochondria mediated caspase dependent pathway was essential in DHTS-induced cytotoxicity. The apoptosis induced by DHTS was suppressed by knockdown of apoptosis inducing factor (AIF), inhibition of caspase-3/9 but was increased after knockdown of caspase-2. Meantime, knockdown of caspase-2, pretreatment with Z-VAD-fmk or NAC (N-Acety-L-Cysteine) efficiently inhibited the autophagy induced by DHTS. A crosstalk between cytochrome c and AIF was also reported.

CONCLUSION

DHTS-induced caspase and ROS dependent apoptosis and autophagy were mediated by mitochondria in colon cancer. DHTS could be a promising leading compound for the development of anti-tumor agent or be developed as an adjuvant drug for colon cancer therapy.

Blockade of TNF-α-induced NF-κB signaling pathway and anti-cancer therapeutic response of dihydrotanshinone I

The nuclear factor-κB (NF-κB) transcription factors control many physiological processes including inflammation, immunity, apoptosis, and angiogenesis. We identified dihydrotanshinone I as an inhibitor of NF-κB activation through our research on Salvia miltiorrhiza Bunge. In this study, we found that dihydrotanshinone I significantly inhibited the expression of NF-κB reporter gene induced by TNF-α in a dose-dependent manner. And dihydrotanshinone I also inhibited TNF-α induced phosphorylation and degradation of IκBα, phosphorylation and nuclear translocation of p65. Furthermore, pretreatment of cells with this compound prevented the TNF-α-induced expression of NF-κB target genes, such as anti-apoptosis (cIAP-1 and FLIP), proliferation (COX-2), invasion (MMP-9), angiogenesis (VEGF), and major inflammatory cytokines (TNF-α, IL-6, and MCP1). We also demonstrated that dihydrotanshinone I potentiated TNF-α-induced apoptosis. Moreover, dihydrotanshinone I significantly impaired activation of extracellular signal-regulated kinase 1/2 (ERK1/2), p38 and stress-activated protein kinase/c-Jun NH2-terminal kinase (JNK/SAPK). In vivo studies demonstrated that dihydrotanshinone I suppressed the growth of HeLa cells in a xenograft tumor model, which could be correlated with its modulation of TNF-α production. Taken together, dihydrotanshinone I could be a valuable candidate for the intervention of NF-κB-dependent pathological conditions such as inflammation and cancer.