Isoalantolactone exerts anti-melanoma effects via inhibiting PI3K/AKT/mTOR and STAT3 signaling in cell and mouse models.

BACKGROUND AND AIM: Although the anti-cancer activity of isoalantolactone (IATL) has been extensively studied, the anti-melanoma effects of IATL are still unknown. Here, we have investigated the anti-melanoma effects and mechanism of action of IATL. MTT and crystal violet staining assays were performed to detect the inhibitory effect of IATL on melanoma cell viability. Apoptosis and cell cycle arrest induced by IATL were examined using flow cytometry. The molecular mechanism of IATL was explored by Western blotting, confocal microscope analysis, molecular docking, and cellular thermal shift assay (CETSA). A B16F10 allograft mouse model was constructed to determine the anti-melanoma effects of IATL in vivo. The results showed that IATL exerted anti-melanoma effects in vitro and in vivo. IATL induced cytoprotective autophagy in melanoma cells by inhibiting the PI3K/AKT/mTOR signaling. Moreover, IATL inhibited STAT3 activation both in melanoma cells and allograft tumors not only by binding to the SH2 domain of STAT3 but also by suppressing the activity of its upstream kinase Src. These findings demonstrate that IATL exerts anti-melanoma effects via inhibiting the STAT3 and PI3K/AKT/mTOR signaling pathways, and provides a pharmacological basis for developing IATL as a novel phytotherapeutic agent for treating melanoma clinically.

Inhibition of Src/STAT3 signaling-mediated angiogenesis is involved in the anti-melanoma effects of dioscin.

Angiogenesis plays an important role in the growth and metastasis of solid tumors including melanoma. Inhibiting tumor-associated angiogenesis is a tactic in treating melanoma. Dioscin restrains angiogenesis in colon tumor and has anti-melanoma effects in cell and animal models. In a previous study, we found that dioscin inhibits Src/STAT3 signaling in melanoma cells. Activation of the Src/STAT3 pathway has been shown to promote tumor angiogenesis. This study aimed to determine whether dioscin's anti-melanoma effects is related to inhibiting Src/STAT3 signaling-mediated angiogenesis. In a B16F10 allograft mouse model, we found that dioscin inhibited melanoma growth and angiogenesis. To exclude the impact of tumor growth on angiogenesis, a chicken chorioallantoic membrane (CAM) model was used to verify the anti-angiogenic effect of dioscin. Results showed that dioscin suppressed vessel formation in CAM. To determine if tumor secreted pro-angiogenic cytokines are involved in the anti-angiogenic effect of dioscin, conditioned media from dioscin-treated A375 melanoma cells were used to culture human umbilical vein endothelial cells (HUVECs), and tube formation was monitored. It was observed that the tube formation of HUVECs was inhibited. Mechanistic studies revealed that dioscin inhibited the activation of Src and STAT3, and lowered mRNA and protein levels of STAT3 transcriptionally-regulated genes, in B16F10 melanomas. ELISA assays showed that dioscin decreased the secretion of MMP-2, MMP-9 and VEGF from A375 cells. Over-activation of STAT3 lessened the effects of dioscin in decreasing the secretion of pro-angiogenic cytokines from melanoma cells, and in inhibiting tube formation of HUVECs cultured with conditioned media from melanoma cell cultures. In summary, we for the first time demonstrated that inhibiting Src/STAT3 signaling-mediated angiogenesis is involved in the anti-melanoma effects of dioscin. This study provides further pharmacological groundwork for developing dioscin as an anti-melanoma agent.

Polyphyllin II Induces Protective Autophagy and Apoptosis via Inhibiting PI3K/AKT/mTOR and STAT3 Signaling in Colorectal Cancer Cells.

Polyphyllin II (PPII) is a natural steroidal saponin occurring in Rhizoma Paridis. It has been demonstrated to exhibit anti-cancer activity against a variety of cancer cells. However, the anti-colorectal cancer (CRC) effects and mechanism of action of PPII are rarely reported. In the present study, we showed that PPII inhibited the proliferation of HCT116 and SW620 cells. Moreover, PPII induced G2/M-phase cell cycle arrest and apoptosis, as well as protective autophagy, in CRC cells. We found that PPII-induced autophagy was associated with the inhibition of PI3K/AKT/mTOR signaling. Western blotting results further revealed that PPII lowered the protein levels of phospho-Src (Tyr416), phospho-JAK2 (Tyr1007/1008), phospho-STAT3 (Tyr705), and STAT3-targeted molecules in CRC cells. The overactivation of STAT3 attenuated the cytotoxicity of PPII against HCT116 cells, indicating the involvement of STAT3 inhibition in the anti-CRC effects of PPII. PPII (0.5 mg/kg or 1 mg/kg, i.p. once every 3 days) suppressed HCT116 tumor growth in nude mice. In alignment with the in vitro results, PPII inhibited proliferation, induced apoptosis, and lowered the protein levels of phospho-STAT3, phospho-AKT, and phospho-mTOR in xenografts. These data suggest that PPII could be a potent therapeutic agent for the treatment of CRC.

Gomisin N Exerts Anti-liver Cancer Effects and Regulates PI3K-Akt and mTOR-ULK1 Pathways in Vitro.

Primary liver cancer is a lethal cancer. The phosphatidylinositol 3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) pathway has been implicated in the pathogenesis of liver cancer. Gomisin N (GN), a lignan isolated from the dried fruits of Schisandra chinensis (Turca.) Baill., has been reported to reduce viability of, and induce apoptosis in, HepG2 liver cancer cells. In preadipocytes, GN was found to inhibit Akt activity. In the present study, Akt signaling-related anti-liver cancer mechanisms of GN were investigated. We confirmed that GN reduces cell viability of, and triggers apoptosis in, more liver cancer cell lines. Mechanistic studies revealed that GN lowers protein levels of phospho-PI3K (p85 tyrosine (Tyr)458), phospho-Akt (serine (Ser)473), and Akt downstream molecules Mcl-1 in HepG2 and HCCLM3 cells. Meanwhile, GN activates mTOR and inhibits ULK1 (a negative downstream effector of mTOR) activities. Activation of mTOR has been reported to suppress ULK1 activity and repress autophagy. Indeed, we observed that GN inhibits autophagy in liver cancer cells. In summary, we for the first time demonstrated that GN inhibits the PI3K-Akt pathway and regulates the mTOR-ULK1 pathway in liver cancer cells.

A TCM formula comprising Sophorae Flos and Lonicerae Japonicae Flos alters compositions of immune cells and molecules of the STAT3 pathway in melanoma microenvironment.

A traditional Chinese medicine (TCM) formula (SL) comprising Sophorae Flos and Lonicerae Japonicae Flos was used for treating melanoma in ancient China. We have previously shown that an ethanolic extract of SL (SLE) possesses anti-melanoma effects and suppresses STAT3 signaling in vitro and in vivo. STAT3 has been linked to the development of melanoma immunosuppressive microenvironment. In this work, we investigated whether SLE inhibits melanoma growth by reprogramming the tumor microenvironment in mouse and co-culture cell models. In B16F10 melanoma-bearing mice, we found that intragastric administration of SLE (1.2 g/kg) dramatically inhibited tumor growth. This observation was associated with the downregulation of protein levels of phospho-STAT3 (Tyr 705) and STAT3-regulated immunosuppressive cytokines, and mRNA levels of STAT3-targeted genes involved in tumor growth and immune evasion. We also observed increased Th, Tc and dendritic cells in the melanomas and spleens in SLE-treated mice compared to that in control mice. In a co-culture system composed of B16F10 cells and mouse primary splenic lymphocytes, it was found that SLE not only inhibited STAT3 activation in B16F10 cells, but also downregulated mRNA levels of STAT3-targeted genes in the splenic lymphocytes. In this co-culture setting, SLE decreased the levels of STAT3-regulated immunosuppressive cytokines, increased the percentages of Th, Tc and dendritic cells as well. Furthermore, effects of SLE on STAT3 phosphorylation, cytokine levels and immune cell subtype percentages were significantly weaker in the B16STAT3C cells (stable cells harboring a constitutively active STAT3 variant STAT3C)/splenic lymphocytes co-culture system than in the B16V cells (cells stably transfected with the empty vector)/splenic lymphocytes co-culture system, indicating that STAT3 over-activation diminishes SLE's effects. In summary, our findings indicate that reprograming the immune microenvironment, partially mediated by inhibiting STAT3 signaling, contributes to the anti-melanoma mechanisms of SLE. This study provides further pharmacological groundwork for developing SLE as a modern agent for melanoma prevention/treatment, and supports the notion that reprograming immunosuppressive microenvironment is a viable anti-melanoma strategy.

The JAK2/STAT3 pathway is involved in the anti-melanoma effects of atractylenolide I.

In this study, we aimed to investigate the anti-melanoma effects and the JAK2/STAT3 pathway-related mechanism of action of atractylenolide I in human melanoma cells. Our results showed that atractylenolide I effectively reduced viability, induced apoptosis and inhibited migration of melanoma cells. Meanwhile, atractylenolide I decreased the protein expression levels of phospho-JAK2 and phospho-STAT3, and in turn downregulated the mRNA levels of STAT3-targeted genes, including Bcl-xL, MMP-2 and MMP-9. Furthermore, the cytotoxic effect of atractylenolide I was attenuated in STAT3-overactivated A375 cells. These findings indicate that inhibition of JAK2/STAT3 signalling contributes to the anti-melanoma effects of atractylenolide I.

Gracillin exerts anti-melanoma effects in vitro and in vivo: role of DNA damage, apoptosis and autophagy.

BACKGROUND: Melanoma is an aggressive cancer. Gracillin has been reported to treat various types of cancer, such as colorectal and lung cancer. However, there is a paucity of research on the anti-melanoma effects of gracillin. PURPOSE: The aim of this study was to assess the anti-melanoma effects and mechanisms of action of gracillin in vitro and in vivo. METHODS: Cell viability was detected using MTT and crystal violet staining assays. Cell proliferation was examined by EdU staining assays. Cell cycle arrest and apoptosis were analyzed by flow cytometry. Autophagic flux was monitored under a confocal microscope. Protein levels were determined by immunoblotting. LY294002 and rapamycin (Rapa) were used to determine the involvement of PI3K/AKT/mTOR signaling in gracillin-mediated autophagy. Signal transducer and activator of transcription 3 (STAT3) was overactivated to explore the contribution of the STAT3 signaling pathway in the anti-melanoma effects of gracillin. A B16F10 allograft mouse model was developed to evaluate the anti-melanoma effects of gracillin in vivo. RESULTS: We demonstrated that in melanoma cells, gracillin inhibited proliferation, induced G0/G1 phase cell cycle arrest, evoked apoptosis, and triggered autophagic cell death. Gracillin induced DNA damage in melanoma cells. Moreover, it suppressed the phosphorylation/activation of PI3K, AKT, mTOR, and 4E-BP1 in melanoma cells. Inhibiting PI3K/AKT and mTOR activity using LY294002 and Rapa, respectively, increased the protein level of LC3B-II in gracillin-treated melanoma cells. Furthermore, gracillin downregulated the protein levels of p-JAK2 (Tyr1007/1008), p-Src (Tyr416), and p-STAT3 (Tyr705) in melanoma cells. Over-expression of STAT3 in A375 cells significantly mitigated the cytotoxic and apoptotic effects of gracillin. In vivo studies showed that gracillin (1 mg/kg or 8 mg/kg, administered intraperitoneally for 16 consecutive days) suppressed B16F10 tumor growth and Src/STAT3 and AKT/mTOR signaling in tumors. No overt toxicity was observed in mice. CONCLUSION: Induction of DNA damage, inhibition of PI3K/AKT/mTOR signaling and suppression of STAT3 signaling are involved in gracillin-mediated cell cycle arrest, autophagic cell death and apoptosis, respectively, in melanoma cells. These findings provide novel insights into the anti-melanoma molecular mechanisms of gracillin, and suggest a potential role of gracillin in melanoma management.

Dietary magnesium is able to influence the relationship between vitamin C and estimated glomerular filtration rate: A cross-sectional study.

The estimated glomerular filtration rate (eGFR) is a comprehensive index that is widely used to assess renal function. Although studies have confirmed a correlation between eGFR and dietary vitamin C, the impact of varying levels of vitamin C on eGFR remains unclear. Additionally, the interaction between dietary magnesium intake and vitamin C concentration on eGFR is not well understood. As such, the objective of this study was to investigate the relationship between dietary magnesium intake and vitamin C in relation to eGFR. This study analyzed the data of consecutive NHANES from 2005 to 2018. We included 17,633 participants aged 20 or older and used multiple linear regression analysis to evaluate the relationship between dietary vitamin C and eGFR. Dietary Mg intake from experimental data was dichotomized into a low dietary Mg intake group (≤254 mg/day) and a normal dietary Mg intake group (>254 mg/day). To evaluate the impact of dietary magnesium intake on eGFR, a multivariable linear regression was conducted utilizing an interaction test between dietary vitamin C and eGFR. We discovered a positive association between dietary vitamin C content and eGFR. The relationship between dietary vitamin C levels and eGFR differed between individuals with low Mg intake and those with normal Mg intake (ß: 2.96 95% CI:1.63 ~ 4.29 vs. ß: 1.05 95% CI: -0.15 to 2.25), and the positive association of high dietary vitamin C content with eGFR was stronger in the low Mg intake group. Furthermore, we observed that dietary magnesium intake significantly altered the positive association between dietary vitamin C and eGFR (interaction value of 0.020). Our experimental study revealed that the interaction between dietary magnesium and dietary vitamin C can significantly impact eGFR. This finding carries significant implications for the treatment of diseases resulting from abnormal eGFR, as well as the selection of clinically relevant drugs.

A traditional prescription comprising Astragali Radix and Schisandra chinensis Fructus induces apoptosis and protective autophagy in hepatocellular carcinoma cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Hepatocellular carcinoma (HCC) poses a growing challenge to global health efforts. The 5-year survival rate of HCC patients is still dismal. A traditional prescription Qi-Wei-Wan (QWW) comprising Astragali Radix and Schisandra chinensis Fructus has traditionally been used for HCC treatment according to traditional Chinese medicine theory, but the pharmacological basis is not clear. AIM OF THE STUDY: This study aims to investigate the anti-HCC effects of an ethanolic extract of QWW (hereafter, QWWE) and the mechanism of action. MATERIALS AND METHODS: An UPLC-Q-TOF-MS/MS method was developed to control the quality of QWWE. Two human HCC cell lines (HCCLM3 and HepG2) and a HCCLM3 xenograft mouse model were employed to investigate the anti-HCC effects of QWWE. The anti-proliferative effect of QWWE in vitro was determined by MTT, colony formation and EdU staining assays. Apoptosis and protein levels were examined by flow cytometry and Western blotting, respectively. Nuclear presence of signal transducer and activator of transcription 3 (STAT3) was examined by immunostaining. Transient transfection of pEGFP-LC3 and STAT3C plasmids was performed to assess autophagy and determine the involvement of STAT3 signaling in QWWE's anti-HCC effects, respectively. RESULTS: We found that QWWE inhibited the proliferation of and triggered apoptosis in HCC cells. Mechanistically, QWWE inhibited the activation of SRC and STAT3 at Tyr416 and Tyr705, respectively; inhibited the nuclear translocation of STAT3; lowered Bcl-2 protein levels, while increased Bax protein levels in HCC cells. Over-activating STAT3 attenuated the cytotoxic and apoptotic effects of QWWE in HCC cells. Moreover, QWWE induced autophagy in HCC cells by inhibiting mTOR signaling. Blocking autophagy with autophagy inhibitors (3-methyladenine and chloroquine) enhanced the cytotoxicity, apoptotic effect and the inhibitory effect on STAT3 activation of QWWE. Intragastric administration of QWWE at 10 mg/kg and 20 mg/kg potently repressed tumor growth and inhibited STAT3 and mTOR signaling in tumor tissues, but did not significantly affect mouse body weight. CONCLUSION: QWWE exhibited potent anti-HCC effects. Inhibiting the STAT3 signaling pathway is involved in QWWE-mediated apoptosis, while blocking mTOR signaling contributes to QWWE-mediated autophagy induction. Blockade of autophagy enhanced the anti-HCC effects of QWWE, indicating that the combination of an autophagy inhibitor and QWWE might be a promising therapeutic strategy for HCC management. Our findings provide pharmacological justifications for the traditional use of QWW in treating HCC.

Chrysoeriol suppresses hyperproliferation of rheumatoid arthritis fibroblast-like synoviocytes and inhibits JAK2/STAT3 signaling.

BACKGROUND: Fibroblast-like synoviocytes (FLS) have cancer cell-like characteristics, such as abnormal proliferation and resistance to apoptosis, and play a pathogenic role in rheumatoid arthritis (RA). Hyperproliferation of RA-FLS that can be triggered by the activation of interleukin-6/signal transducer and activator of transcription 3 (IL-6/STAT3) signaling destructs cartilage and bone in RA patients. Chrysoeriol is a flavone found in medicinal herbs such as Chrysanthemi Indici Flos (the dried capitulum of Chrysanthemum indicum L.). These herbs are commonly used in treating RA. Chrysoeriol has been shown to exert anti-inflammatory effects and inhibit STAT3 signaling in our previous studies. This study aimed to determine whether chrysoeriol inhibits hyperproliferation of RA-FLS, and whether inhibiting STAT3 signaling is one of the underlying mechanisms. METHODS: IL-6/soluble IL-6 receptor (IL-6/sIL-6R)-stimulated RA-FLS were used to evaluate the effects of chrysoeriol. CCK-8 assay and crystal violet staining were used to examine cell proliferation. Annexin V-FITC/PI double staining was used to detect cell apoptosis. Western blotting was employed to determine protein levels. RESULTS: Chrysoeriol suppressed hyperproliferation of, and evoked apoptosis in, IL-6/sIL-6R-stimulated RA-FLS. The apoptotic effect of chrysoeriol was verified by its ability to cleave caspase-3 and caspase-9. Mechanistic studies revealed that chrysoeriol inhibited activation/phosphorylation of Janus kinase 2 (JAK2, Tyr1007/1008) and STAT3 (Tyr705); decreased STAT3 nuclear level and down-regulated protein levels of Bcl-2 and Mcl-1 that are transcriptionally regulated by STAT3. Over-activation of STAT3 significantly diminished anti-proliferative effects of chrysoeriol in IL-6/sIL-6R-stimulated RA-FLS. CONCLUSIONS: We for the first time demonstrated that chrysoeriol suppresses hyperproliferation of RA-FLS, and suppression of JAK2/STAT3 signaling contributes to the underlying mechanisms. This study provides pharmacological and chemical justifications for the traditional use of chrysoeriol-containing herbs in treating RA, and provides a pharmacological basis for developing chrysoeriol into a novel anti-RA agent.

A two-herb formula inhibits STAT3 signaling and exerts anti-melanoma effects in cell and animal models.

ETHNOPHARMACOLOGICAL RELEVANCE: Malignant melanoma is a fatal cancer. Signal transducer and activator of transcription 3 (STAT3) has been proposed as a therapeutic target of melanoma. An herbal formula Huai-Hua-San (HHS) comprising Sophorae Flos (SF) and Gardeniae Fructus (GF) is traditionally used for treating cancers including melanoma, but the pharmacological basis is unknown. AIMS OF THIS STUDY: This study aimed to investigate the anti-melanoma effects of an ethanolic extract of HHS (HHSE), and explore the involvement of STAT3 signaling in the effects. MATERIALS AND METHODS: An UPLC-TOF/MS method was developed to control the quality of HHSE. A B16F10 allograft mouse model and three melanoma cell lines (B16F10, A375 and A2058) were used to determine the anti-melanoma effects of HHSE. Dacarbazine (DTIC) and Stattic were used as positive controls. Cell viability was detected using MTT and crystal violet staining assays. Cell apoptosis was analyzed by flow cytometry after the cells were stained with Annexin-V/PI. Cell invasive ability was examined using the transwell assay. Protein levels were determined by Western blotting. RESULTS: The contents of crocin I, crocin II, quercetin and kaempferol in HHSE were 0.59%, 0.98%, 4.66% and 1.15%, respectively. A clinically relevant dose of HHSE (0.1 g/kg/day, i.g. for 15 consecutive days) significantly suppressed B16F10 tumor growth in mice. HHSE dose-dependently reduced cell viability and dampened invasion of, and induced apoptosis in, melanoma cells. Mechanistic studies revealed that HHSE inhibited the phosphorylation/activation of STAT3 in B16F10 allografts and in cultured melanoma cells. In cell models, HHSE also inhibited the phosphorylation of STAT3 upstream kinases, JAK2 (Tyr1007/1008) and Src (Tyr416), lowered STAT3 nuclear levels, and down-regulated the protein levels of STAT3-targeted molecules. Over-activation of STAT3 in A375 cells significantly attenuated the cytotoxic effects of HHSE. CONCLUSIONS: HHSE exhibits anti-melanoma effects in cell and mouse models. Inhibition of STAT3 signaling contributes to the anti-melanoma mechanisms of HHSE. Our findings lay a groundwork for developing HHSE as a modern agent for melanoma management, and provide pharmacological justifications for the traditional use of HHS in treating melanoma.

A two-herb formula inhibits hyperproliferation of rheumatoid arthritis fibroblast-like synoviocytes.

Fibroblast-like synoviocytes (FLS) play a pathogenic role in rheumatoid arthritis (RA). STAT3 signaling is activated in FLS of RA patients (RA-FLS), which in turn causes RA-FLS hyperproliferation. RL is a traditional remedy for treating inflammatory diseases in China. It comprises Rosae Multiflorae Fructus and Lonicerae Japonicae Flos. A standardized ethanolic extract of RL (RLE) has been shown to exert anti-arthritic effects in collagen-induced arthritis (CIA) rats. Some constituents of RLE were reported to inhibit JAK2/STAT3 signaling in rat FLS. Here, we determined whether RLE inhibits FLS hyperproliferation, and explored the involvement of STAT3 signaling in this inhibition. In joints of CIA rats, RLE increased apoptotic FLS. In IL-6/sIL-6R-stimulated RA-FLS, RLE reduced cell viability and evoked cell apoptosis. In synovial tissues of CIA rats, RLE lowered the protein level of phospho-STAT3. In IL-6/sIL-6R-stimulated RA-FLS, RLE inhibited activation/phosphorylation of STAT3 and JAK2, decreased the nuclear localization of STAT3, and downregulated protein levels of Bcl-2 and Mcl-1. Over-activation of STAT3 diminished RLE's anti-proliferative effects in IL-6/sIL-6R-stimulated RA-FLS. In summary, RLE inhibits hyperproliferation of FLS in rat and cell models, and suppression of STAT3 signaling contributes to the underlying mechanisms. This study provides further pharmacological groundwork for developing RLE as a modern anti-arthritic drug.

Activation of STAT3 is a key event in TLR4 signaling-mediated melanoma progression.

Malignant melanoma is aggressive and has a high mortality rate. Toll-like receptor 4 (TLR4) has been linked to melanoma growth, angiogenesis and metastasis. However, signal transduction mediated by TLR4 for driving melanoma progression is not fully understood. Signal transducer and activator of transcription 3 (STAT3) has been identified as a major oncogene in melanoma progression. We found: that TLR4 expression positively correlates with activation/phosphorylation of STAT3 in human melanoma samples; that TLR4 ligands activate STAT3 through MYD88 and TRIF in melanoma cells; and that intratumoral activation of TLR4 increases STAT3 activation in the tumor and promotes tumor growth, angiogenesis, epithelial-mesenchymal transition (EMT) and the formation of an immunosuppressive tumor microenvironment in mice. Further, we found that the effects mediated by activating TLR4 are weakened by suppressing STAT3 function with a dominant negative STAT3 variant in melanoma. Collectively, our work identifies STAT3 activation as a key event in TLR4 signaling-mediated melanoma progression, shedding new light on the pathophysiology of melanoma.

Inhibiting the Src/STAT3 signaling pathway contributes to the anti-melanoma mechanisms of dioscin.

Late stage melanoma is associated with a high mortality rate. Signal transducer and activator of transcription 3 (STAT3) is currently a target for melanoma treatment as it is constitutively activated with high frequency in melanoma. Dioscin is a natural steroid saponin that is present in several medical herbs. A previous study demonstrated that dioscin inhibits STAT3 signaling in a cerebral ischemia-reperfusion injury rat model. Furthermore, dioscin has been reported to exert anti-melanoma effects in B16 melanoma cells and a B16 allograft mouse model. The present study investigated whether inhibition of STAT3 signaling is involved in the anti-melanoma effects of dioscin. The results of the present study demonstrated that dioscin significantly decreased viability, induced apoptosis and suppressed migration of human A375 melanoma cells and murine B16F10 melanoma cells. Furthermore, dioscin inhibited the phosphorylation of STAT3 and Src (an upstream kinase of STAT3), and downregulated mRNA levels of STAT3-targeted genes, including B-cell lymphoma-2, cyclin D1 and matrix metalloproteinase-2. In addition, overexpression of STAT3 decreased the anti-proliferative effects of dioscin. Overall, the results of the present study indicate that inhibiting the Src/STAT3 signaling pathway contributes to the anti-melanoma molecular mechanisms of dioscin. These results provide further pharmacological groundwork for developing dioscin as a novel anti-melanoma agent.

Chrysoeriol ameliorates TPA-induced acute skin inflammation in mice and inhibits NF-κB and STAT3 pathways.

BACKGROUND: Chrysoeriol is a flavone found in diverse dietary and medicinal herbs such as Lonicerae Japonicae Flos (the dried flower bud or newly bloomed flower of Lonicera japonica Thunb.). These herbs are commonly used for treating inflammatory diseases. Herbal extracts containing chrysoeriol have been shown to have anti-inflammatory effects and inhibit nuclear factor-kappa B (NF-κB) signaling. Some of these extracts can inhibit signal transducers and activators of transcription 3 (STAT3) signaling in cancer cells. PURPOSE: This study aimed to determine whether chrysoeriol has anti-inflammatory effects and whether NF-κB and STAT3 pathways are involved in the effects. STUDY DESIGN AND METHODS: A TPA (12-O-tetradecanoylphorbol-13-acetate)-induced ear edema mouse model and LPS-stimulated RAW264.7 cells were used to evaluate the effects of chrysoeriol. Griess reagent was used to measure the production of nitric oxide (NO). Western blot and enzyme-linked immunosorbent assays were employed to detect protein levels. RT-qPCR analyses were used to detect mRNA levels. Haematoxylin and eosin (H&E) staining was employed to examine the pathological conditions in animal tissues. RESULTS: In the mouse model, chrysoeriol ameliorated acute skin inflammation, evidenced by reduced ear thickness, ear weight and number of inflammatory cells in inflamed ear tissues. The compound lowered protein levels of phospho-p65 (Ser536), phospho-STAT3 (Tyr705), inducible nitric oxide synthases (iNOS), cyclooxygenase-2 (COX-2), interleukin 6 (IL-6), IL-1ß and tumor necrosis factor α (TNF-α) in mouse swollen ears. In LPS-stimulated RAW264.7 cells, chrysoeriol also lowered levels of these proteins. In addition, chrysoeriol decreased the production of NO and prostaglandin E2; inhibited the phosphorylation of inhibitor of κB (Ser32), p65 (Ser536) and Janus kinase 2 (Tyr1007/1008); decreased nuclear localization of p50, p65 and STAT3; and down-regulated mRNA levels of pro-inflammatory cytokines IL-6, IL-1ß and TNF-α that are transcriptionally regulated by NF-κB and STAT3 in the cell model. CONCLUSION: We for the first time demonstrated that chrysoeriol ameliorates TPA-induced ear edema in mice, and that inhibition of JAK2/STAT3 and IκB/p65 NF-κB pathways are involved in the anti-inflammatory effects of chrysoeriol. This study provides chemical and pharmacological justifications for the use of chrysoeriol-containing herbs in treating inflammatory diseases, and provides pharmacological groundwork for developing chrysoeriol as a novel anti-inflammatory agent.

MiR-let-7a/f-CCR7 signaling is involved in the anti-metastatic effects of an herbal formula comprising Sophorae Flos and Lonicerae Japonicae Flos in melanoma.

BACKGROUND: Metastasized melanoma is extremely difficult to treat. Activation of C-C chemokine receptor type 7 (CCR7) has been linked to melanoma metastasis. CCR7 can be directly regulated by miR-let-7. We have previously shown that an ethanolic extract of an herbal formula comprising Sophorae Flos and Lonicerae Japonicae Flos (SLE) inhibits melanoma cell migration and invasion. PURPOSE: In this study, we determined whether SLE suppresses melanoma metastasis, and whether regulation of miR-let-7a/f-CCR7 signaling is involved in the effect. STUDY DESIGN AND METHODS: Small RNA sequencing was conducted to compare miRNA expression profiles of B16F10 tumors dissected from SLE-treated or untreated mice. Western blot and RT-qPCR analyses were employed to examine protein and miRNA levels, respectively. A B16F10 melanoma lung metastasis mouse model was used to evaluate the effects of SLE on melanoma metastasis. MiR-let-7a/f-knockdown and CCR7-overexpression cell models were used to investigate the involvement of miR-let-7a/f-CCR7 signaling in the anti-metastatic effects of SLE. RESULTS: It was found that SLE upregulated levels of miR-let-7a/f in B16F10 melanoma tissues. SLE significantly elevated levels of miR-let-7a/f, lowered the protein level of CCR7, inhibited the phosphorylation of CCR7 downstream molecules p38 and JNK in B16F10 and A375 melanoma cells. SLE inhibited B16F10 melanoma lung metastasis in mice. SLE upregulated levels of miR-let-7a/f, and lowered protein levels of CCR7, MMP-2, MMP-9, phospho-p38 (Thr180/Tyr182) and phospho-JNK (Thr183/Tyr185) in melanoma-invaded lung tissues. Knockdown of miR-let-7a/f diminished the effects of SLE on CCR7 signaling in, and invasion of, melanoma cells. Overexpression of CCR7 lessened the effects of SLE in inhibiting the phosphorylation of p38 and JNK in, and the invasive capability of, melanoma cells. CONCLUSION: We for the first time demonstrated that SLE inhibits melanoma metastasis in mice, and that regulation of the miR-let-7a/f-CCR7 pathway contributes to the anti-metastatic mechanisms of SLE. These findings provide a pharmacological basis for developing SLE as a modern agent for treating metastatic melanoma. Additionally and importantly, this study suggests that regulating the miR-let-7a/f-CCR7 pathway is a novel strategy for controlling melanoma metastasis.

Antrodia camphorata Mycelia Exert Anti-liver Cancer Effects and Inhibit STAT3 Signaling in vitro and in vivo.

Hepatocellular carcinoma (HCC), the major form of primary liver cancer, is a common cause of cancer-related death worldwide. Signal transducer and activator of transcription 3 (STAT3) signaling is constantly activated in HCC and has been proposed as a chemotherapeutic target for HCC. Antrodia camphorata (AC), a medicinal mushroom unique to Taiwan, is traditionally used for treating HCC. Whereas natural AC is scarce, cultured AC mycelia are becoming alternatives. In this study, we investigated the anti-HCC effects of the ethyl acetate fraction of an ethanolic extract of AC mycelia (EEAC), particularly exploring the involvement of STAT3 signaling in these effects. We found that EEAC reduced cell viability, induced apoptosis, and retarded migration and invasion in cultured HepG2 and SMMC-7721 cells. Immunoblotting results showed that EEAC downregulated protein levels of phosphorylated and total STAT3 and JAK2 (an upstream kinase of STAT3) in HCC cells. Real-time PCR analyses showed that STAT3, but not JAK2, mRNA levels were decreased by EEAC. EEAC also lowered the protein level of nuclear STAT3, decreased the transcriptional activity of STAT3, and downregulated protein levels of STAT3-targeted molecules, including anti-apoptotic proteins Bcl-xL and Bcl-2, and invasion-related proteins MMP-2 and MMP-9. Over-activation of STAT3 in HCC cells diminished the cytotoxic effects of EEAC. In SMMC-7721 cell-bearing mice, EEAC (100 mg/kg, i.g. for 18 days) significantly inhibited tumor growth. Consistent with our in vitro data, EEAC induced apoptosis and suppressed JAK2/STAT3 activation/phosphorylation in the tumors. Taken together, EEAC exerts anti-HCC effects both in vitro and in vivo; and inhibition of STAT3 signaling is, at least in part, responsible for these effects. We did not observe significant toxicity of EEAC in normal human liver-derived cells, nude mice and rats. Our results provide a pharmacological basis for developing EEAC as a safe and effective agent for HCC management.