Effect of Pin1 inhibitor juglone on proliferation, migration and angiogenic ability of breast cancer cell line MCF7Adr

Juglone suppresses vasculogenic mimicry in glioma through inhibition of HuR-mediated VEGF-A expression

Vasculogenic mimicry (VM) serves as a vascular-like channel that provides important substances for tumor growth and is a primary factor in glioblastoma (GBM) drug resistance. Human Antigen R (HuR)-an mRNA-binding protein-is highly expressed in GBM, closely related to tumor progression, and deemed a potential drug target. Although some small-molecule compounds have been identified to disrupt HuR binding to target mRNA, they remain in the preclinical research stage, suggesting the need for further validation and development of HuR inhibitors. In our study, we aim to screen for potential HuR inhibitors and investigate their efficacy and molecular mechanisms in GBM. We employed the fluorescence polarization method to identify HuR inhibitors from a natural compound library, confirming the efficacy of juglone in effectively inhibiting the binding of HuR to AREVegf-a. Further validation of the binding of juglone to HuR at the protein level was conducted through electrophoretic mobility shift analysis, surface plasmon resonance, and molecular docking. Furthermore, juglone demonstrated inhibitory effects on glioma growth and VM formation in vitro and in vivo. Moreover, it was observed that juglone reversed epithelial-mesenchymal transition by inhibiting the VEGF-A/VEGFR2/AKT/SNAIL signaling pathway. Finally, we established the capability of juglone to target HuR in U251 cells through HuR knockdown, mRNA stability, and cell thermal shift assays. Therefore, this study identifies juglone as a novel HuR inhibitor, potentially offering promise as a lead compound for anti-VM therapy in GBM by targeting HuR. Abbreviations: AKT, protein kinase B; ARE, adenine-and uridine-rich elements; CETSA, cellular thermal shift assay; DMEM, Dulbecco's modified Eagle's medium; ELISA, enzyme linked immune sorbent assay; EMSA, electrophoretic mobility shift assay; EMT, epithelial mesenchymal transition; FP, fluorescence polarization; GBM, glioblastoma; HTS, high-throughput screening; HuR, human antigen R; IF, Immunofluorescence; PAS, periodic acid-Schiff; PI3K, phosphoinositide-3 kinase; qRT-PCR, quantitative real-time PCR; RRMs, RNA recognition motifs; SPR, surface plasmon resonance. TMZ, temozolomide; VM, vasculogenic mimicry; VEGF-A, Vascular endothelial growth factor-A; VEGFR2, Vascular endothelial growth factor receptor-2.

Molecular biological mechanism of action in cancer therapies: Juglone and its derivatives, the future of development

Juglone (5 - hydroxy - 1, 4 - naphthalene diketone) is a kind of natural naphthoquinone, present in the roots, leaves, nut-hulls, bark and wood of walnut trees. Recent studies have found that Juglone has special significance in the treatment of cancer, which plays a significant role in the resistance of cancer cell proliferation, induction of cancer cell apoptosis, induction of autophagy, anti-angiogenesis and inhibition of cancer cell migration and invasion, etc. Additionally, its derivatives also play a tumor suppressive effect. In conclusion, Juglone and its derivatives have been identified as effective anticancer drugs. This paper reviews action mechanisms of Juglone and its derivatives in cancer treatment.

Potential Anti-Tumor Activity of Kefir-Induced Juglone and Resveratrol Fractions Against Ehrlich Ascites Carcinoma-Bearing BALB/C Mice

We investigated the potential influence of kefir-induced juglone and resveratrol fractions (JRK) against Ehrlich Ascites Carcinoma (EAC) bearing BALB/c male mice. Kefir yeast was grown in the cell culture supplemented with juglone and resveratrol (1:2). After 48 h incubation, JRK solution was applied (0.1 mL/day i.p.) to the EAC-bearing mice throughout five days. Molecular regulatory mechanisms of apoptotic and anti-apoptotic pathway components were evaluated in the plasma of mice and isolated EAC cells with ELISA, qRT-PCR, and immunocytchemical experiments. EAC-induced upregulation in Bcl-2 and downregulation in Caspase-3 were normalized with JRK in the plasma of mice. Additionally, JRK upregulated the expression levels of apoptotic Bax, p53, Caspase-3,8,9, and APAF-1 proteins together with BAX, CASPASE-8, and CASPASE-9 genes in isolated EAC cells. These changes were also associated with decreased expression levels of anti-apoptotic Bcl-2 and Bcl-xl proteins. Immunocytochemical studies also confirmed the activation of apoptotic pathways and repression of anti-apoptotic proteins in EAC cells with JRK treatment. JRK activates apoptotic pathway and inhibits anti-apoptotic genes and proteins in Ehrlich ascites carcinoma- bearing BALB/c mice that could be beneficial in cancer treatment.

Mission Possible: Advances in MYC Therapeutic Targeting in Cancer

MYC is a master transcriptional regulator that controls almost all cellular processes. Over the last several decades, researchers have strived to define the context-dependent transcriptional gene programs that are controlled by MYC, as well as the mechanisms that regulate MYC function, in an effort to better understand the contribution of this oncoprotein to cancer progression. There are a wealth of data indicating that deregulation of MYC activity occurs in a large number of cancers and significantly contributes to disease progression, metastatic potential, and therapeutic resistance. Although the therapeutic targeting of MYC in cancer is highly desirable, there remain substantial structural and functional challenges that have impeded direct MYC-targeted drug development and efficacy. While efforts to drug the ‘undruggable’ may seem futile given these challenges and considering the broad reach of MYC, significant strides have been made to identify points of regulation that can be exploited for therapeutic purposes. These include targeting the deregulation of MYC transcription in cancer through small-molecule inhibitors that induce epigenetic silencing or that regulate the G-quadruplex structures within the MYC promoter. Alternatively, compounds that disrupt the DNA-binding activities of MYC have been the long-standing focus of many research groups, since this method would prevent downstream MYC oncogenic activities regardless of upstream alterations. Finally, proteins involved in the post-translational regulation of MYC have been identified as important surrogate targets to reduce MYC activity downstream of aberrant cell stimulatory signals. Given the complex regulation of the MYC signaling pathway, a combination of these approaches may provide the most durable response, but this has yet to be shown. Here, we provide a comprehensive overview of the different therapeutic strategies being employed to target oncogenic MYC function, with a focus on post-translational mechanisms.

Juglone eliminates MDSCs accumulation and enhances antitumor immunity

Myeloid-derived suppressor cells (MDSCs) contribute to immune activity suppression and promote the tumor progression. Elimination of MDSCs is a promising cancer therapeutic strategy, and some chemotherapeutic agents have been reported to hamper tumor progression by suppressing MDSCs. Juglone has been showed to exert a direct cytotoxic effect on tumor cells. However, the effect of juglone on MDSCs and anti-tumor immune statue has remained unexplored. In our study, we observed that juglone suppressed tumor growth and metastasis markedly, and the tumor growth suppression in immunocompetent mice was more drastic than that in immunodeficient mice. Juglone reduced the accumulation of MDSCs and increased IFN-γ production by CD8⁺ T cells. Consistently, juglone affected myeloid cells differentiation and maturation, impairing the immunosuppressive functions of MDSCs. Moreover, juglone down-regulated the level of IL-1β which was mediating accumulation of MDSCs. In addition, juglone inhibited 5FU-induced liver injury in a colorectal carcinoma-bearing mice model. Thus, our work suggests that the anti-tumor effect of juglone is mediated, at least in part, by eliminating accumulation of MDSCs.

Knockdown of the prolyl isomerase Pin1 inhibits Hep-2 cell growth, migration, and invasion by targeting the β-catenin signaling pathway

There is increasing evidence indicating that peptidylprolyl cis/trans isomerase, NIMA-interacting 1 (Pin1) plays a decisive role in a variety of cancers. Nevertheless, its function in laryngeal squamous cell carcinoma (LSCC) has not been elaborated. The aim of this study is to determine the role of Pin1 in LSCC. Here, we established stably transfected Hep-2 cells with low expression of Pin1. Intriguingly, cell proliferation, migration, and invasion was significantly inhibited in Pin1-silenced Hep-2 cells. Similarly, knockdown of Pin1 induced apoptosis of Hep-2 cells, as evidenced by increased expression of cleaved-caspase-3, cleaved-PARP, and bax, and decreased expression of bcl2. We also demonstrated that silencing of Pin1 down-regulated β-catenin and cyclin D1 expression. Inversely, over-expression of β-catenin reversed the inhibiting effect of Pin1 silencing on Hep-2 cells. Moreover, we proved that knockdown of Pin1 inhibited tumorigenesis of Hep-2 cells in vivo. Taken together, we demonstrate that silencing of Pin1 effectively suppresses the growth of Hep-2 cells through β-catenin, indicating that Pin1 possess the potential to serve as a therapeutic target for the treatment of LSCC.

Natural Products to Fight Cancer: A Focus on Juglans regia

Even if cancer represents a burden for human society, an exhaustive cure has not been discovered yet. Low therapeutic index and resistance to pharmacotherapy are two of the major limits of antitumour treatments. Natural products represent an excellent library of bioactive molecules. Thus, tapping into the natural world may prove useful in identifying new therapeutic options with favourable pharmaco-toxicological profiles. Juglans regia, or common walnut, is a very resilient tree that has inhabited our planet for thousands of years. Many studies correlate walnut consumption to beneficial effects towards several chronic diseases, such as cancer, mainly due to the bioactive molecules stored in different parts of the plant. Among others, polyphenols, quinones, proteins, and essential fatty acids contribute to its pharmacologic activity. The present review aims to offer a comprehensive perspective about the antitumour potential of the most promising compounds stored in this plant, such as juglanin, juglone, and the ellagitannin-metabolites urolithins or deriving from walnut dietary intake. All molecules and a chronic intake of the fruit provide tangible anticancer effects. However, the scarcity of studies on humans does not allow results to be conclusive.

Juglone reduces growth and migration of U251 glioblastoma cells and disrupts angiogenesis

Accumulating data show that prolylisomerase (Pin1) is overexpressed in human glioblastoma multiforme (GBM) specimens. Therefore, Pin1 inhibitors should be investigated as a new chemotherapeutic drug that may enhance the clinical management of human gliomas. Recently, juglone, a Pin1 inhibitor, was shown to exhibit potent anticancer activity in various tumor cells, but its role in human glioma cells remains unknown. In the present study, we determined if juglone exerts antitumor effects in the U251 human glioma cell line and investigated its potential underlying molecular mechanisms. Cell survival, apoptosis, migration, angiogenesis and molecular targets were identified with multiple detection techniques including the MTT cell proliferation assay, dual acridine orange/ethidium bromide staining, electron microscopy, Transwell migration assay, chick chorioallantoic membrane assay, quantitative real-time polymerase chain reaction and immunoblotting. The results showed that 5–20 µM juglone markedly suppressed cell proliferation, induced apoptosis, and enhanced caspase-3 activity in U251 cells in a dose- and time-dependent manner. Moreover, juglone inhibited cell migration and the formation of new blood vessels. At the molecular level, juglone markedly suppressed Pin1 levels in a time-dependent manner. TGF-β1/Smad signaling, a critical upstream regulator of miR-21, was also suppressed by juglone. Moreover, the transient overexpression of Pin1 reversed its antitumor effects in U251 cells and inhibited juglone-mediated changes to the TGF-β1/miR-21 signaling pathway. These findings suggest that juglone inhibits cell growth by causing apoptosis, thereby inhibiting the migration of U251 glioma cells and disrupting angiogenesis; and that Pin1 is a critical target for juglones antitumor activity. The present study provides evidence that juglone has in vitro efficacy against glioma. Therefore, additional studies are warranted to examine the clinical potential of juglone in human gliomas.

Juglone ameliorates skin wound healing by promoting skin cell migration through Rac1/Cdc42/PAK pathway

Skin cell regeneration and wound healing are key processes in the recovery from skin injuries. Rapid cell migration and regeneration of skin cells lead to faster and better healing of wounded skin. In the present study, we aimed to investigate the wound healing potential of juglone, a naturally occurring Pin1 inhibitor found in walnuts. Cultured skin cells (NHDF and HaCaT) and hairless mice were treated with juglone after wound creation to examine its effects on cell migration and wound healing rate. The expressions of cell migration related proteins (Rac1, Cdc42, and α-PAK), collagen deposition, and angiogenesis were analyzed. Juglone treatment resulted in faster rate of growth and migration and recovered cell morphology, particularly at a concentration of 5 µM, in skin cells compared to the untreated group. In vivo experiments showed that mice treated with juglone showed faster wound healing rate with better skin morphology and collagen deposition than the vehicle group. Furthermore, juglone increased the activation and/or expression of Cdc42, Rac1, and α-pak in HaCaT cells, and resulted in enhanced angiogenesis in endothelial cells (HUVECs). Juglone also activated MAPKs signaling by activation of ERK, JNK, and p38 proteins. Taken together, these data suggest that juglone may be a potential candidate for wound healing and skin regeneration which ameliorates wound healing mainly by promoting skin cell migration through Rac1/Cdc42/PAK pathway.