Distinct binding conformations of epinephrine with α- and ß-adrenergic receptors.

Agonists targeting α2-adrenergic receptors (ARs) are used to treat diverse conditions, including hypertension, attention-deficit/hyperactivity disorder, pain, panic disorders, opioid and alcohol withdrawal symptoms, and cigarette cravings. These receptors transduce signals through heterotrimeric Gi proteins. Here, we elucidated cryo-EM structures that depict α2A-AR in complex with Gi proteins, along with the endogenous agonist epinephrine or the synthetic agonist dexmedetomidine. Molecular dynamics simulations and functional studies reinforce the results of the structural revelations. Our investigation revealed that epinephrine exhibits different conformations when engaging with α-ARs and ß-ARs. Furthermore, α2A-AR and ß1-AR (primarily coupled to Gs, with secondary associations to Gi) were compared and found to exhibit different interactions with Gi proteins. Notably, the stability of the epinephrine-α2A-AR-Gi complex is greater than that of the dexmedetomidine-α2A-AR-Gi complex. These findings substantiate and improve our knowledge on the intricate signaling mechanisms orchestrated by ARs and concurrently shed light on the regulation of α-ARs and ß-ARs by epinephrine.

The role of Ginkgo Folium on antitumor: Bioactive constituents and the potential mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: Ginkgo biloba L. is a well-known and highly regarded resource in Chinese traditional medicine due to its effectiveness and safety. Ginkgo Folium, the leaf of Ginkgo biloba L., contains biologically active constituents with diverse pharmacological activities. Recent studies have shown promising antitumor effects of the bioactive constituents found in Ginkgo Folium against various types of cancer cells, highlighting its potential as a natural source of antitumor agents. Further research is needed to elucidate the underlying mechanisms and optimize its therapeutic potential. AIM OF THE REVIEW: To provide a detailed understanding of the pharmacological activities of Ginkgo Folium and its potential therapeutic benefits for cancer patients. MATERIALS AND METHODS: In this study, we conducted a thorough and systematic search of multiple online databases, including PubMed, Web of Science, Medline, using relevant keywords such as "Ginkgo Folium," "flavonoids," "terpenoids," "Ginkgo Folium extracts," and "antitumor" to cover a broad range of studies that could inform our review. Additionally, we followed a rigorous selection process to ensure that the studies included in our review met the predetermined inclusion criteria. RESULTS: The active constituents of Ginkgo Folium primarily consist of flavonoids and terpenoids, with quercetin, kaempferol, isorhamnetin, ginkgolides, and bilobalide being the major compounds. These active constituents exert their antitumor effects through crucial biological events such as apoptosis, cell cycle arrest, autophagy, and inhibition of invasion and metastasis via modulating diverse signaling pathways. During the process of apoptosis, active constituents primarily exert their effects by modulating the caspase-8 mediated death receptor pathway and caspase-9 mediated mitochondrial pathway via regulating specific signaling pathways. Furthermore, by modulating multiple signaling pathways, active constituents effectively induce G1, G0/G1, G2, and G2/M phase arrest. Among these, the pathways associated with G2/M phase arrest are particularly extensive, with the cyclin-dependent kinases (CDKs) being most involved. Moreover, active constituents primarily mediate autophagy by modulating certain inflammatory factors and stressors, facilitating the fusion stage between autophagosomes and lysosomes. Additionally, through the modulation of specific chemokines and matrix metalloproteinases, active constituents effectively inhibit the processes of epithelial-mesenchymal transition (EMT) and angiogenesis, exerting a significant impact on cellular invasion and migration. Synergistic effects are observed among the active constituents, particularly quercetin and kaempferol. CONCLUSION: Active components derived from Ginkgo Folium demonstrate a comprehensive antitumor effect across various levels and pathways, presenting compelling evidence for their potential in new drug development. However, in order to facilitate their broad and adaptable clinical application, further extensive experimental investigations are required to thoroughly explore their efficacy, safety, and underlying mechanisms of action.

Therapeutic effect of Sheng Mai San, a traditional Chinese medicine formula, on inflammatory bowel disease via inhibition of NF-κB and NLRP3 inflammasome signaling.

Introduction: Inflammatory bowel disease (IBD) is a globally emergent chronic inflammatory disease which commonly requires lifelong care. To date, there remains a pressing need for the discovery of novel anti-inflammatory therapeutic agents against this disease. Sheng Mai San (SMS) is a traditional Chinese medicine prescription with a long history of use for treating Qi and Yin deficiency and recent studies have shown that SMS exhibits anti-inflammatory potential. However, the effects of SMS on the gastrointestinal system remain poorly studied, and its therapeutic potential and underlying molecular mechanisms in IBD have yet to be discovered. In this study, we examined the therapeutic efficacy of SMS in IBD and its anti-inflammatory activity and underlying molecular mechanism, in vivo and in vitro. Methods: The therapeutic efficacy of SMS in IBD was assessed in the DSS-induced acute colitis mouse model. Body weight, stool consistency, rectal bleeding, colon length, organ coefficient, cytokine levels in colon tissues, infiltration of immune cells, and colon pathology were evaluated. The anti-inflammatory activity of SMS and related molecular mechanisms were further examined in lipopolysaccharide (LPS)-induced macrophages via assessment of pro-inflammatory cytokine secretion and NF-κB, MAPK, STAT3, and NLRP3 signalling. Results: SMS significantly ameliorated the severity of disease in acute colitis mice, as evidenced by an improvement in disease activity index, colon morphology, and histological damage. Additionally, SMS reduced pro-inflammatory cytokine production and infiltration of immune cells in colon tissues. Furthermore, in LPS-induced macrophages, we demonstrated that SMS significantly inhibited the production of cytokines and suppressed the activation of multiple pro-inflammatory signalling pathways, including NF-κB, MAPK, and STAT3. SMS also abolished NLRP3 inflammasome activation and inhibited subsequent caspase-1 activation and IL-1ß secretion, suggesting a new therapeutic target for the treatment of IBD. These mechanistic findings were also confirmed in in vivo assays. Conclusion: This study presents the anti-inflammatory activity and detailed molecular mechanism of SMS, in vitro and in vivo. Importantly, we highlight for the first time the potential of SMS as an effective therapeutic agent against IBD.

Roles of Fascin in Dendritic Cells.

Dendritic cells (DCs) are professional antigen-presenting cells that play a crucial role in activating naive T cells through presenting antigen information, thereby influencing immunity and anti-cancer responses. Fascin, a 55-kDa actin-bundling protein, is highly expressed in mature DCs and serves as a marker protein for their identification. However, the precise role of fascin in intratumoral DCs remains poorly understood. In this review, we aim to summarize the role of fascin in both normal and intratumoral DCs. In normal DCs, fascin promotes immune effects through facilitating DC maturation and migration. Through targeting intratumoral DCs, fascin inhibitors enhance anti-tumor immune activity. These roles of fascin in different DC populations offer valuable insights for future research in immunotherapy and strategies aimed at improving cancer treatments.

ß-Elemene induced ferroptosis via TFEB-mediated GPX4 degradation in EGFR wide-type non-small cell lung cancer.

INTRODUCTION: ß-Elemene (ß-ELE), derived from Curcuma wenyujin, has anticancer effect on non-small cell lung cancer (NSCLC). However, the potential target and detail mechanism were still not clear. TFEB is the master regulator of lysosome biogenesis. Ferroptosis, a promising strategy for cancer therapy could be triggered via suppression on glutathione peroxidase 4 (GPX4). Weather TFEB-mediated lysosome degradation contributes to GPX4 decline and how ß-ELE modulates on this process are not clear. OBJECTIVES: To observe the action of ß-ELE on TFEB, and the role of TFEB-mediated GPX4 degradation in ß-ELE induced ferroptosis. METHODS: Surface plasmon resonance (SPR) and molecular docking were applied to observe the binding affinity of ß-ELE on TFEB. Activation of TFEB and lysosome were observed by immunofluorescence, western blot, flow cytometry and qPCR. Ferroptosis induced by ß-ELE was observed via lipid ROS, a labile iron pool (LIP) assay and western blot. A549TFEB KO cells were established via CRISPR/Cas9. The regulation of TFEB on GPX4 and ferroptosis was observed in ß-ELE treated A549WT and A549TFEB KO cells, which was further studied in orthotopic NOD/SCID mouse model. RESULTS: ß-ELE can bind to TFEB, notably activate TFEB, lysosome and transcriptional increase on downstream gene GLA, MCOLN1, SLC26A11 involved in lysosome activity in EGFR wild-type NSCLC cells. ß-ELE increased GPX4 ubiquitination and lysosomal localization, with the increase on lysosome degradation of GPX4. Furthermore, ß-ELE induced ferroptosis, which could be promoted by TFEB overexpression or compromised by TFEB knockout. Genetic knockout or inactivation of TFEB compromised ß-ELE induced lysosome degradation of GPX4, which was further demonstrated in orthotopic NSCLC NOD/SCID mice model. CONCLUSION: This study firstly demonstrated that TFEB promoted GPX4 lysosome degradation contributes to ß-ELE induced ferroptosis in EGFR wild-type NSCLC, which gives a clue that TFEB mediated GPX4 degradation would be a novel strategy for ferroptosis induction and NSCLC therapy.

TFEB: a double-edged sword for tumor metastasis.

Transcription factor EB, a member of the microphthalmia-associated transcription factor (MiTF/TFE) family, is a master regulator of autophagy, lysosome biogenesis, and TAMs. Metastasis is one of the main reasons for the failure of tumor therapy. Studies on the relationship between TFEB and tumor metastasis are contradictory. On the positive side, TFEB mainly affects tumor cell metastasis via five aspects, including autophagy, epithelial-mesenchymal transition (EMT), lysosomal biogenesis, lipid metabolism, and oncogenic signaling pathways; on the negative side, TFEB mainly affects tumor cell metastasis in two aspects, including tumor-associated macrophages (TAMs) and EMT. In this review, we described the detailed mechanism of TFEB-mediated regulation of metastasis. In addition, we also described the activation and inactivation of TFEB in several aspects, including the mTORC1 and Rag GTPase systems, ERK2, and AKT. However, the exact process by which TFEB regulates tumor metastasis remains unclear in some pathways, which requires further studies.

Hyperprogression, a challenge of PD-1/PD-L1 inhibitors treatments: potential mechanisms and coping strategies.

Immunotherapy is now a mainstay in cancer treatments. Programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) immune checkpoint inhibitor (ICI) therapies have opened up a new venue of advanced cancer immunotherapy. However, hyperprogressive disease (HPD) induced by PD-1/PD-L1 inhibitors caused a significant decrease in the overall survival (OS) of the patients, which compromise the efficacy of PD-1/PD-L1 inhibitors. Therefore, HPD has become an urgent issue to be addressed in the clinical uses of PD-1/PD-L1 inhibitors. The mechanisms of HPD remain unclear, and possible predictive factors of HPD are not well understood. In this review, we summarized the potential mechanisms of HPD and coping strategies that can effectively reduce the occurrence and development of HPD.

Structural basis and mechanism of activation of two different families of G proteins by the same GPCR.

The ß1-adrenergic receptor (ß1-AR) can activate two families of G proteins. When coupled to Gs, ß1-AR increases cardiac output, and coupling to Gi leads to decreased responsiveness in myocardial infarction. By comparative structural analysis of turkey ß1-AR complexed with either Gi or Gs, we investigate how a single G-protein-coupled receptor simultaneously signals through two G proteins. We find that, although the critical receptor-interacting C-terminal α5-helices on Gαi and Gαs interact similarly with ß1-AR, the overall interacting modes between ß1-AR and G proteins vary substantially. Functional studies reveal the importance of the differing interactions and provide evidence that the activation efficacy of G proteins by ß1-AR is determined by the entire three-dimensional interaction surface, including intracellular loops 2 and 4 (ICL2 and ICL4).

Ginkgetin derived from Ginkgo biloba leaves enhances the therapeutic effect of cisplatin via ferroptosis-mediated disruption of the Nrf2/HO-1 axis in EGFR wild-type non-small-cell lung cancer.

BACKGROUND: Cisplatin (DDP) is the first-in-class drug for advanced and non-targetable non-small-cell lung cancer (NSCLC). A recent study indicated that DDP could slightly induce non-apoptotic cell death ferroptosis, and the cytotoxicity was promoted by ferroptosis inducer. The agents enhancing the ferroptosis may therefore increase the anticancer effect of DDP. Several lines of evidence supporting the use of phytochemicals in NSCLC therapy. Ginkgetin, a bioflavonoid derived from Ginkgo biloba leaves, showed anticancer effects on NSCLC by triggering autophagy. Ferroptosis can be triggered by autophagy, which regulates redox homeostasis. Thus, we aimed to elucidate the possible role of ferroptosis involved in the synergistic effect of ginkgetin and DDP in cancer therapy. METHODS: The promotion of DDP-induced anticancer effects by ginkgetin was examined via a cytotoxicity assay and western blot. Ferroptosis triggered by ginkgetin in DDP-treated NSCLC was observed via a lipid peroxidation assay, a labile iron pool assay, western blot, and qPCR. With ferroptosis blocking, the contribution of ferroptosis to ginkgetin + DDP-induced cytotoxicity, the Nrf2/HO-1 axis, and apoptosis were determined via a luciferase assay, immunostaining, chromatin immunoprecipitation (CHIP), and flow cytometry. The role of ferroptosis in ginkgetin + DDP-treated NSCLC cells was illustrated by the application of ferroptosis inhibitors, which was further demonstrated in a xenograft nude mouse model. RESULTS: Ginkgetin synergized with DDP to increase cytotoxicity in NSCLC cells, which was concomitant with increased labile iron pool and lipid peroxidation. Both these processes were key characteristics of ferroptosis. The induction of ferroptosis mediated by ginkgetin was further confirmed by the decreased expression of SLC7A11 and GPX4, and a decreased GSH/GSSG ratio. Simultaneously, ginkgetin disrupted redox hemostasis in DDP-treated cells, as demonstrated by the enhanced ROS formation and inactivation of the Nrf2/HO-1 axis. Ginkgetin also enhanced DDP-induced mitochondrial membrane potential (MMP) loss and apoptosis in cultured NSCLC cells. Furthermore, blocking ferroptosis reversed the ginkgetin-induced inactivation of Nrf2/HO-1 as well as the elevation of ROS formation, MMP loss, and apoptosis in DDP-treated NSCLC cells. CONCLUSION: This study is the first to report that ginkgetin derived from Ginkgo biloba leaves promotes DDP-induced anticancer effects, which can be due to the induction of ferroptosis.

Synergistic anti-cancer activity by the combination of TRAIL/APO-2L and celastrol.

The present study demonstrates that the combination of TRAIL/APO-2L and celastrol exerts strong synergistic antiproliferative effect against human cancer cells including ovary cancer OVCAR-8, colon cancer SW620, and lung cancer 95-D, with the combination indices below 0.8. Moreover, the in vivo antitumor efficacy of TRAIL/APO-2L was dramatically increased by celastrol. These enhanced anticancer activities were accompanied by the prompt onset of caspase-mediated apoptosis. Taken together, our data firstly demonstrate the synergistic anticancer capabilities achieved by combining TRAIL/APO-2L and celastrol, and moreover, open new opportunities to enhance the effectiveness of future treatment regimens using TRAIL/APO-2L.

Protective effect of gan mai da zao decoction in unpredictable chronic mild stress-induced behavioral and biochemical alterations.

AIM: Growing evidence indicates that the glutamatergic system, especially the abnormalities of glutamate and N-methyl-D-aspartate (NMDA) receptors contribute to the pathophysiology and possibly the pathogenesis of major depressive disorders. This study is to evaluate the effect of gan mai da zao (GMDZ) decoction on glutamate and NMDA receptor in unpredictable chronic mild stress (UCMS) rats. MATERIALS AND METHODS: Sucrose preference test and open field test were used to estimate the depressive-like behaviors of UCMS rats. Glutamate levels and NMDA receptor subunits (NR1, NR2A and NR2B) in the frontal cortex and hippocampus were determined by HPLC-FLD and by western-blot respectively. RESULTS: 32 days UCMS induced depressive-like behaviors, increased glutamate concentration and decreased NMDA receptor subunits NR2A and NR2B in the frontal cortex and hippocampus of rats. However, NR1 expression remained constant in stressed rats compared with normal. The GMDZ decoction alleviated the depressive-like behavior, decreased glutamate level, and increased expression of NMDA receptor subunit NR2A and NR2B in the frontal cortex and hippocampus of stressed rats. CONCLUSIONS: These results suggest that GMDZ treatment reversed chronic unpredictable stress-induced depressive-like behaviors in UCMS rats, possibly via reducing glutamate levels and increasing the NMDA receptor subunits NR2A and NR2B in frontal cortex and hippocampus.

Berberine Improves Inflammatory Responses of Diabetes Mellitus in Zucker Diabetic Fatty Rats and Insulin-Resistant HepG2 Cells through the PPM1B Pathway.

Berberine (BBR), a natural compound extracted from a Chinese herb, has been shown to effectively attenuate insulin resistance (IR) and inflammation in the clinic. However, its ameliorative mechanism against IR is not well defined. This study is aimed at investigating the effect of BBR and protein phosphatase, Mg2+/Mn2+-dependent 1B (PPM1B) on IR. Biochemical measurements and liver histopathology were detected using the biochemical analyzer and HE staining in ZDF rats, respectively. Microarray analysis of liver tissues was performed, and differentially expressed gene (DEG) levels were examined by quantitative real-time PCR (qPCR) and Western blot. Additionally, the effect of BBR was also explored in HepG2-IR cells. The glucose oxidase method and the fluorescent glucose analog were used to detect glucose consumption and uptake, respectively. The PKA inhibitor H89, ELISA, qPCR, Western blot, and immunofluorescence staining were employed to estimate the expression levels of related signaling pathways. To evaluate the roles of PPM1B, HepG2-IR cells were stably infected with lentivirus targeting PPM1B. The administration of BBR drastically decreased the body weight, urine volume, blood glucose, blood urea nitrogen (BUN), CHOL, hepatic index levels, and pathologic changes and improved ALB levels in ZDF rats with PPM1B upregulation. Furthermore, BBR effectively improves glucose consumption, uptake, and inflammation in HepG2-IR cells. The knockdown of PPM1B expression aggravated the inflammatory response and glycometabolism disorder in HepG2-IR cells. Mechanistically, a reversal in the expression of cAMP, PKA, PPM1B, PPARγ, LRP1, GLUT4, NF-κB p65, JNK, pIKKß Ser181, IKKß, IRS-1 Ser307, IRS-1, IRS-2 Ser731, IRS-2, PI3K p85, and AKT Ser473 contributes to ameliorate IR in HepG2-IR cells with BBR treatment. Altogether, these results suggest that BBR might regulate IR progression through the regulation of the cAMP, PKA, PPM1B, PPARγ, LRP1, GLUT4, NF-κB p65, JNK, pIKKß Ser181, IKKß, IRS-1 Ser307, IRS-1, IRS-2 Ser731, IRS-2, PI3K p85, and AKT Ser473 expression in the liver.

Cancer Treatment by Using Traditional Chinese Medicine: Probing Active Compounds in Anti-multidrug Resistance During Drug Therapy.

The main challenge of cancer treatment is multidrug resistance during chemotherapy. Cancer cell can evade cell death during every round of orthodox chemotherapy drugs, consequently being resistant after several rounds of standard drug treatment. One of the regimens to address this multidrug resistance problem is by drug combination. However, synthetic drugs always have problems of strong side effects and toxicity. Natural compounds deriving from traditional Chinese medicine are known to have low toxicity and genuine promising effects in reversing multidrug resistance, either induced by orthodox chemotherapeutic or targeted therapy drugs. Numerous mechanisms including suppression of drug efflux, detoxifying systems, DNA repair systems, and anti-apoptosis pathways were responsible for such process. A range of natural compounds functioned on the suppression of apoptosis are widely reported, which include flavonoids, terpenoids, alkaloids, quinones, xanthones, saponins and polysaccharides. Here, this review summarized comprehensive data from in vitro and in vivo studies to elucidate the functional roles of natural compounds in reversing multidrug resistance during cancer therapy.

The extract of Polygoni Cuspidati Rhizoma et Radix suppresses the vascular endothelial growth factor-induced angiogenesis.

BACKGROUND: Polygoni Cuspidati Rhizoma et Radix (PCRR; the root and rhizome of Polygonum cuspidatum Sieb. et Zucc) is a traditional Chinese medicine for the treatment of inflammation, hyperlipemia, favus, jaundice and scald. HYPOTHESIS/PURPOSE: The extract of PCRR inhibits vascular endothelial growth factor (VEGF)-induced angiogenesis. The hypothesis is supported by analysis of PCRR extract and investigation of pharmacological role and signaling mechanism of PCRR extract in regulating angiogenic responses. STUDY DESIGN: The PCRR ethanolic extract was examined for its inhibitory effects on angiogenesis based on VEGF-treated human umbilical vein endothelial cells and in zebrafish model METHODS: The effects and signaling mechanism of a standardized ethanolic extract of PCRR were tested on cell proliferation, migration and tube formation in VEGF-treated human umbilical vein endothelial cells, and which was further validated in zebrafish embryo model. RESULTS: The treatment of PCRR extract in cultured endothelial cells inhibited VEGF-induced cell proliferation, cell migration and tube formation in a dose-dependent manner and also suppressed the formation of sub-intestinal vessels in zebrafish embryos. Moreover, the applied PCRR extract suppressed VEGF-induced phosphorylations of VEGF receptor 2 (VEGFR2) and JNK. Thus, the site of effect triggered by PCRR was proposed to be mediated by VEGFR2. To further support this notion, the phosphorylations of Erk, Akt and eNOS, induced by VEGF, were markedly reduced under the challenge of PCRR extract: the reductions were subsequently further decreased in the present of inhibitors of Erk, Akt and eNOS. In parallel, the formation of ROS induced by VEGF in cultured endothelial cells was markedly reduced in the present of PCRR extract. CONCLUSION: Collectively, our studies demonstrated the pharmacological role and signaling mechanism of PCRR in regulation of angiogenic responses, which supported further evaluation and development of PCRR as a potential therapeutic agent for the treatment and prevention of diseases related with angiogenesis.

The WT1/MVP-Mediated Stabilization on mTOR/AKT Axis Enhances the Effects of Cisplatin in Non-small Cell Lung Cancer by a Reformulated Yu Ping Feng San Herbal Preparation.

Chemo-resistance is an obstacle in therapy of lung cancer. Alternative therapy of using herbal medicine has been proposed to resolve this obstacle. Yu Ping Feng San (YPFS), a common Chinese herbal medicinal mixture, has been reported to show anti-drug resistance on cisplatin (DDP), a common lung cancer drug. To optimize the anti-cancer function of YPFS, different Chinese herbal extracts having known function to overcome lung cancer were screened in combining with YPFS, as to increase the efficacy of DDP in drug resistance lung cancer cell, A549/DDP. Amongst these herbal extracts, Ginkgo Folium exhibited the most promoting sensitized effect. This revised herbal formula, named as YPFS+GF, promoted the DDP-induced toxicity by over 2-fold as compared to that of YPFS alone; this potentiation was confirmed by inducing cell apoptosis. The anti-drug resistance of YPFS, triggered by an increase of intracellular concentration of DDP, was accompanied by an increased expression and activity of WT1, which consequently decreased the transcript level of MVP. In addition, the MVP-mediated downstream effector mTOR2/AKT was disrupted after application of YPFS+GF in DDP-treated A549/DDP cell: this disruption was characterized by the decline of mTORC2 components, e.g., Rictor, p-mTOR, as well as the phosphorylation level of its downstream protein AKT. The disruption on mTORC2/AKT could be reversed by mTORC2 inducer insulin and promoted by mTORC2 inhibitor PP242. Thus, the anti-drug resistance of YPFS+GF in DDP-treated lung cancer cells might be mediated by the down regulation of WT1/MVP axis, as well as the downstream anti-apoptotic pathway of mTORC2/AKT signaling. Herbal medicine is one of the main adjuvant therapies in non-small cell lung cancer, and this novel herbal formula supports the prescription of traditional Chinese medicine in cancer treatment.

Ginkgetin induces autophagic cell death through p62/SQSTM1-mediated autolysosome formation and redox setting in non-small cell lung cancer.

Promoting cell death by autophagy could be a novel treatment for cancer. The major player in autophagy, p62, serves as a good therapeutic target. Ginkgetin, a biflavonoid from Ginkgo biloba leaves, exhibited promising anticancer activity in non-small cell lung cancer cell lines, with an IC50 lower than that of cisplatin. This anticancer effect of ginkgetin was illustrated in a xenograft nude mouse model. Ginkgetin induced autophagic cell death in A549 cells, and this effect was markedly reversed by chemical and genetic approaches. Ginkgetin showed potential binding affinity to p62. Upregulation of p62 through chemical and genetic means decreased cell death, lysosome acidification, and autophagosome formation, which consequently disrupted autolysosome formation. In addition, the decreased autophagy induced by p62 overexpression increased Nrf2/ARE activity and the oxygen consumption rate and decreased on formation of reactive oxygen species. These phenomena were exhibited in a reciprocal manner when p62 was knocked down. Thus, p62 may be a potential target in ginkgetin-induced autophagic cell death, and ginkgetin could be developed as a novel anticancer drug.

Yu Ping Feng San reverses cisplatin-induced multi-drug resistance in lung cancer cells via regulating drug transporters and p62/TRAF6 signalling.

Yu Ping Feng San (YPFS), an ancient Chinese herbal decoction composed of Astragali Radix, Atractylodis Macrocephalae Rhizoma and Saposhnikoviae Radix, has been used in the clinic for treating immune deficiency. In cancer therapy, YPFS is being combined with chemotherapy drugs to achieve improved efficacy; however, scientific evidence to illustrate this combination effect is lacking. The present study aims to demonstrate the anti-drug resistance of YPFS in cisplatin (DDP)-resistant non-small cell lung cancer cells (A549/DDP). The application of YPFS exhibited a synergistic enhancement of DDP-induced cytotoxicity as well as of the apoptotic signalling molecules. DDP-induced expression of the multi-drug-resistance efflux transporters was markedly reduced in the presence of YPFS, resulting in a higher intracellular concentration of DDP. In addition, the application of YPFS increased DDP-induced ROS accumulation and MMP depletion, decreased p62/TRAF6 signalling in DDP-treated A549/DDP cells. The co-treatment of DDP and YPFS in tumour-bearing mice reduced the tumour size robustly (by more than 80%), which was much better than the effect of DDP alone. These results indicate that YPFS can notably improve the DDP-suppressed cancer effect, which may be a consequence of the elevation of intracellular DDP via the drug transporters as well as the down regulation of p62/TRAF6 signalling.

Inactivation of hypoxia-induced YAP by statins overcomes hypoxic resistance tosorafenib in hepatocellular carcinoma cells.

Sorafenib is a multikinase inhibitor used as a first-line treatment for advanced hepatocellular carcinoma (HCC), but it has shown modest to low response rates. The characteristic tumour hypoxia of advanced HCC maybe a major factor underlying hypoxia-mediated treatment failure. Thus, it is urgent to elucidate the mechanisms of hypoxia-mediated sorafenib resistance in HCC. In this study, we found that hypoxia induced the nuclear translocation of Yes associate-Protein (YAP) and the subsequent transactivation of target genes that promote cell survival and escape apoptosis, thereby leading to sorafenib resistance. Statins, the inhibitors of hydroxymethylglutaryl-CoA reductase, could ameliorate hypoxia-induced nuclear translocation of YAP and suppress mRNA levels of YAP target genes both in vivo and in vitro. Combined treatment of statins with sorafenib greatly rescued the loss of anti-proliferative effects of sorafenib under hypoxia and improved the inhibitory effects on HepG2 xenograft tumour growth, accompanied by enhanced apoptosis as evidenced by the increased sub-G1 population and PARP cleavage. The expression levels of YAP and its target genes were highly correlated with poor prognosis and predicted a high risk of HCC patients. These findings collectively suggest that statins utilization maybe a promising new strategy to counteract hypoxia-mediated resistance to sorafenib in HCC patients.

Tirapazamine sensitizes hepatocellular carcinoma cells to topoisomerase I inhibitors via cooperative modulation of hypoxia-inducible factor-1α.

Topoisomerase I inhibitors are a class of anticancer drugs with a broad spectrum of clinical activity. However, they have limited efficacy in hepatocellular cancer. Here, we present in vitro and in vivo evidence that the extremely high level of hypoxia-inducible factor-1α (HIF-1α) in hepatocellular carcinoma is intimately correlated with resistance to topoisomerase I inhibitors. In a previous study conducted by our group, we found that tirapazamine could downregulate HIF-1α expression by decreasing HIF-1α protein synthesis. Therefore, we hypothesized that combining tirapazamine with topoisomerase I inhibitors may overcome the chemoresistance. In this study, we investigated that in combination with tirapazamine, topoisomerase I inhibitors exhibited synergistic cytotoxicity and induced significant apoptosis in several hepatocellular carcinoma cell lines. The enhanced apoptosis induced by tirapazamine plus SN-38 (the active metabolite of irinotecan) was accompanied by increased mitochondrial depolarization and caspase pathway activation. The combination treatment dramatically inhibited the accumulation of HIF-1α protein, decreased the HIF-1α transcriptional activation, and impaired the phosphorylation of proteins involved in the homologous recombination repair pathway, ultimately resulting in the synergism of these two drugs. Moreover, the increased anticancer efficacy of tirapazamine combined with irinotecan was further validated in a human liver cancer Bel-7402 xenograft mouse model. Taken together, our data show for the first time that HIF-1α is strongly correlated with resistance to topoisomerase I inhibitors in hepatocellular carcinoma. These results suggest that HIF-1α is a promising target and provide a rationale for clinical trials investigating the efficacy of the combination of topoisomerase I inhibitors and tirapazamine in hepatocellular cancers.