Involvement of E-cadherin/AMPK/mTOR axis in LKB1-induced sensitivity of non-small cell lung cancer to gambogic acid

Preclinical evidence using synthetic compounds and natural products indicates that AMPK represents a potential pharmacological target for the therapy of pulmonary diseases

Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) is a highly conserved eukaryotic enzyme discovered as a key regulator of cellular energy homeostasis, with anti-inflammation, antioxidative stress, anticancer, and antifibrosis beneficial effects. AMPK is dysregulated in human pulmonary diseases such as acute lung injury, nonsmall cell lung cancer, pulmonary fibrosis, chronic obstructive pulmonary disease, and asthma. This review provides an overview of the beneficial role of natural, synthetic, and Chinese traditional medicines AMPK modulators in pulmonary diseases, and highlights the role of the AMPK signaling pathway in the lung, emphasizing the importance of finding lead compounds and drugs that can target and modulate AMPK to treat the lung diseases.

Targeting the key players of phenotypic plasticity in cancer cells by phytochemicals

Plasticity of phenotypic traits refers to an organism's ability to change in response to environmental stimuli. As a result, the response may alter an organism's physiological state, morphology, behavior, and phenotype. Phenotypic plasticity in cancer cells describes the considerable ability of cancer cells to transform phenotypes through non-genetic molecular signaling activities that promote therapy evasion and tumor metastasis via amplifying cancer heterogeneity. As a result of metastable phenotypic state transitions, cancer cells can tolerate chemotherapy or develop transient adaptive resistance. Therefore, new findings have paved the road in identifying factors and agents that inhibit or suppress phenotypic plasticity. It has also investigated novel multitargeted agents that may promise new effective strategies in cancer treatment. Despite the efficiency of conventional chemotherapeutic agents, drug toxicity, development of resistance, and high-cost limit their use in cancer therapy. Recent research has shown that small molecules derived from natural sources are capable of suppressing cancer by focusing on the plasticity of phenotypic responses. This systematic, comprehensive, and critical review analyzes the current state of knowledge regarding the ability of phytocompounds to target phenotypic plasticity at both preclinical and clinical levels. Current challenges/pitfalls, limitations, and future perspectives are also discussed.

Emerging tendencies for the nano-delivery of gambogic acid: a promising approach in oncotherapy

Despite the advancements in cancer therapies during the past few years, chemo/photo resistance, severe toxic effects, recurrence of metastatic tumors, and non-selective targeting remain incomprehensible. Thus, much effort has been spent exploring natural anticancer compounds endowed with biosafety and high effectiveness in cancer prevention and therapy. Gambogic acid (GA) is a promising natural compound in cancer therapy. It is the major xanthone component of the dry resin extracted from the Garcinia hanburyi Hook. f. tree. GA has significant antiproliferative effects on different types of cancer, and it exerts its anticancer activities through various pathways. Nonetheless, the clinical translation of GA has been hampered, partly due to its water insolubility, low bioavailability, poor pharmacokinetics, rapid plasma clearance, early degradation in blood circulation, and detrimental vascular irritation. Lately, procedures have been invented demonstrating the ability of nanoparticles to overcome the challenges associated with the clinical use of natural compounds both in vitro and in vivo. This review sheds light on the recent emerging trends for the nanodelivery of GA to cancer cells. To the best of our knowledge, no similar recent review described the different nanoformulations designed to improve the anticancer therapeutic activity and targeting ability of GA.

Lycorine suppresses the malignancy of breast carcinoma by modulating epithelial mesenchymal transition and β-catenin signaling

Lycorine, an isoquinoline alkaloid can exhibit significant anti-cancer effects. The present study was conducted to illustrate the underlying mechanisms of action of lycorine on breast carcinoma under in vitro and in vivo settings Tandem Mass Tag assay and Kyoto Encyclopedia of Genes and Genomes analysis revealed that 20 signaling pathways were closely related to tumorigenesis, especially Wnt signaling pathway and tight junctions. The results demonstrated that lycorine evidently inhibited the proliferation of MDA-MB-231 and MCF-7 cells with IC50 values of 1.84 ± 0.21 μM and 7.76 ± 1.16 μM, respectively. It also blocked cell cycle in G2/M phase, caused a decrease in mitochondrial membrane potential, and induced apoptosis pathways through regulating caspase-3, caspase-8, caspase-9, and PARP expression. Moreover, lycorine effectively repressed the β-catenin signaling and reversed epithelial-mesenchymal transition (EMT) process. Furthermore, 4T1/Luc homograft tumor model was used to further demonstrate that lycorine significantly inhibited the growth and metastasis of breast tumor. These findings highlight the significance of lycorine as potential anti-neoplastic agent to combat breast cancer.

PDT-sensitized ROS-responsive dextran nanosystem for maximizing antitumor potency of multi-target drugs

The heterogeneity of tumor microenvironment leads to uneven distribution of bio-stimuli. Thus, the multi-site delivery efficiency of responsive drug delivery systems (DDS) inner tumor was always limited. Herein, we proposed a combination strategy of photodynamic therapy (PDT) with ROS-responsive nanosystem which was constructed from dextran-phenylboronic acid pinacol ester conjugates. This combination utilized PDT to amplify and homogenize tissular oxidation level, and achieve effective multi-site response and release of multi-target drugs like gambogic acid (GA). Our research demonstrated the successful preparation of GA and protoporphyrin IX (PpIX) co-loaded nanoparticles, and the PDT-mediated spatiotemporal controlled multi-site drug release in simulated conditions. Furthermore, data from in vitro and in vivo researches on B16F10 cells, HUVEC, and B16F10-bearing C57BL/6 mice potently confirmed the enhanced multi-mechanism regulations of GA mediated by the effective and homogeneous tumoral release. This tactic based on bio-stimuli amplification and homogenization proposes a paradigm to maximize the potency of multi-target drugs.

Potential Application of Gambogic Acid for Retarding Renal Cyst Progression in Polycystic Kidney Disease

Abnormal cell proliferation and accumulation of fluid-filled cysts along the nephrons in polycystic kidney disease (PKD) could lead to a decline in renal function and eventual end-stage renal disease (ESRD). Gambogic acid (GA), a xanthone compound extracted from the brownish resin of the Garcinia hanburyi tree, exhibits various pharmacological properties, including anti-inflammation, antioxidant, anti-proliferation, and anti-cancer activity. However, its effect on inhibiting cell proliferation in PKD is still unknown. This study aimed to determine the pharmacological effects and detailed mechanisms of GA in slowing an in vitro cyst growth model of PKD. The results showed that GA (0.25–2.5 μM) significantly retarded MDCK cyst growth and cyst formation in a dose-dependent manner, without cytotoxicity. Using the BrdU cell proliferation assay, it was found that GA (0.5–2.5 μM) suppressed MDCK and Pkd1 mutant cell proliferation. In addition, GA (0.5–2.5 μM) strongly inhibited phosphorylation of ERK1/2 and S6K expression and upregulated the activation of phosphorylation of AMPK, both in MDCK cells and Pkd1 mutant cells. Taken together, these findings suggested that GA could retard MDCK cyst enlargement, at least in part by inhibiting the cell proliferation pathway. GA could be a natural plant-based drug candidate for ADPKD intervention.

Anticancer Properties and Mechanism of Action of Oblongifolin C, Guttiferone K and Related Polyprenylated Acylphloroglucinols

Polyprenylated acylphloroglucinols represent an important class of natural products found in many plants. Among them, the two related products oblongifolin C (Ob-C) and guttiferone K (Gt-K) isolated from Garcinia species (notably from edible fruits), have attracted attention due to their marked anticancer properties. The two compounds only differ by the nature of the C-6 side chain, prenyl (Gt-K) or geranyl (Ob-C) on the phloroglucinol core. Their origin, method of extraction and biological properties are presented here, with a focus on the targets and pathways implicated in their anticancer activities. Both compounds markedly reduce cancer cell proliferation in vitro, as well as tumor growth and metastasis in vivo. They are both potent inducer of tumor cell apoptosis, and regulation of autophagy flux is a hallmark of their mode of action. The distinct mechanism leading to autophagosome accumulation in cells and the implicated molecular targets are discussed. The specific role of the chaperone protein HSPA8, known to interact with Ob-C, is addressed. Molecular models of Gt-K and Ob-C bound to HSPA8 provide a structural basis to their common HSPA8-binding recognition capacity. The review shed light on the mechanism of action of these compounds, to encourage their studies and potential development.

Targeting the ILK/YAP axis by LFG-500 blocks epithelial-mesenchymal transition and metastasis

Metastasis is the main cause of mortality in patients with cancer. Epithelial-mesenchymal transition (EMT), a crucial process in cancer metastasis, is an established target for antimetastatic drug development. LFG-500, a novel synthetic flavonoid, has been revealed as a potential antitumor agent owing to its various activities, including modulation of EMT in the inflammatory microenvironment. Here, using a transforming growth factor beta (TGF-β)-induced EMT models, we found that LFG-500 inhibited EMT-associated migration and invasion in human breast cancer, MCF-7, and lung adenocarcinoma, A549, cell lines, consistent with the observed downregulation of YAP activity. Further studies demonstrated that LGF-500-induced suppression of YAP activation was mediated by integrin-linked kinase (ILK), suggesting that the ILK/YAP axis might be feasible target for anti-EMT and antimetastatic treatments, which was verified by a correlation analysis with clinical data and tumor specimens. Hence, our data support the use of LGF-500 as an antimetastatic drug in cancer therapy and provide evidence that the ILK/YAP axis is a feasible biomarker of cancer progression and a promising target for repression of EMT and metastasis in cancer therapy.

RSPH14 regulates the proliferation, cell cycle progression and apoptosis of non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) is the most common subtype of lung cancer and it is characterized by a high incidence. It is important to understand the molecular mechanisms that determine the progression and metastasis of NSCLC in order to develop more effective therapies and identify novel diagnostic indicators of NSCLC. RSPH14 has been reported to be related to multiple human diseases, including duodenal adenocarcinoma and meningiomas, but the role of RSPH14 in NSCLC remains unclear. The present study aimed to investigate the molecular function and clinical significance of RSPH14 in NSCLC. Analyses of public datasets and clinical samples demonstrated that RSPH14 expression was upregulated in NSCLC samples compared with normal samples. In addition, high RSPH14 expression was associated with a shorter overall survival time in patients with NSCLC. Notably, RSPH14 knockdown suppressed the proliferation and cell cycle progression, and enhanced the apoptosis of NSCLC cells. Mechanically, Tandem Mass Tag analysis demonstrated that RSPH14 can affect multiple processes, including the AMPK signaling pathway, calcium ion import regulation, glucose transmembrane transporter activity, and glucose transmembrane transport. Taken together, the results of the present study suggest that RSPH14 may be a promising prognostic factor and therapeutic target for NSCLC.

MicroRNA-197-3p mediates damage to human coronary artery endothelial cells via targeting TIMP3 in Kawasaki disease

Kawasaki disease (KD) causes cardiovascular system injury in children. However, the pathogenic mechanisms of KD have not been well defined. Recently, strong correlation between aberrant microRNAs and KD nosogenesis has been revealed. A role of microRNA-197-3p (miR-197-3p) in the pathogenesis of KD is identified in the present study. Cell proliferation assay showed human coronary artery endothelial cells (HCAECs) were suppressed by serum from KD patients, which was correlated with high levels of miR-197-3p in both KD serum and HCAECs cultured with KD serum. The inhibition of HCAECs by miR-197-3p was confirmed by cells expressing miR-197-3p mimic and miR-197-3p inhibitor. Comparative proteomics analysis and Ingenuity Pathway Analysis (IPA) revealed TIMP3 as a potential target of miR-197-3p, which was demonstrated by western blot and dual-luciferase reporter assays. Subsequently, by detecting the endothelium damage markers THBS1, VWF, and HSPG2, the role of miR-197-3p/TIMP3 in KD-induced damage to HCAECs was confirmed, which was further validated by a KD mouse model in vivo. The expressions of miR-197-3p and its target, TIMP3, are dramatically variational in KD serum and HCAECs cultured with KD serum. Increased miR-197-3p induces HCAECs abnormal by restraining TIMP3 expression directly. Hence, dysregulation of miR-197-3p/TIMP3 expression in HCAECs may be an important mechanism in cardiovascular endothelium injury in KD patients, which offers a feasible therapeutic target for KD treatment.

Therapeutic potential of AMPK signaling targeting in lung cancer: Advances, challenges and future prospects

Lung cancer (LC) is a leading cause of death worldwide with high mortality and morbidity. A wide variety of risk factors are considered for LC development such as smoking, air pollution and family history. It appears that genetic and epigenetic factors are also potential players in LC development and progression. AMP-activated protein kinase (AMPK) is a signaling pathway with vital function in inducing energy balance and homeostasis. An increase in AMP:ATP and ADP:ATP ratio leads to activation of AMPK signaling by upstream mediators such as LKB1 and CamKK. Dysregulation of AMPK signaling is a common finding in different cancers, particularly LC. AMPK activation can significantly enhance LC metastasis via EMT induction. Upstream mediators such as PLAG1, IMPAD1, and TUFM can regulate AMPK-mediated metastasis. AMPK activation can promote proliferation and survival of LC cells via glycolysis induction. In suppressing LC progression, anti-tumor compounds including metformin, ginsenosides, casticin and duloxetine dually induce/inhibit AMPK signaling. This is due to double-edged sword role of AMPK signaling in LC cells. Furthermore, AMPK signaling can regulate response of LC cells to chemotherapy and radiotherapy that are discussed in the current review.

New Delivery Route of Gambogic Acid Via Skin for Topical Targeted Therapy of Cutaneous Melanoma and Reduction of Systemic Toxicity

Cutaneous melanoma is the deadliest form of skin cancer, and gambogic acid (GA) exhibits potent anti-melanoma activity. However, clinical application of GA via intravenous injection and oral administration is limited by systemic toxicity and rapid metabolism in the blood. Here, we developed a new, topical route of GA delivery for anti-melanoma activity and reduction of systemic toxicity. The results indicated that the barrier of the stratum corneum (SC) and low diffusion of GA in the hydrophilic viable skin (epidermis and dermis) limited the GA penetration through intact skin. The combination of azone (AZ) and propylene glycol (PG) showed obvious synergistic effects on skin penetration by GA via improving the permeability of the SC and greatly increasing the skin accumulation of GA, thereby forming a high drug concentration in the skin and achieving a topical targeted treatment of melanoma. In addition, GA (AZ-PG) achieved the same anti-melanoma effect via topical delivery as via intravenous injection. Intravenous injection and oral administration of GA induced remarkable pathological changes in various organs in mice, whereas GA was not toxic to various organs or to the skin via topical delivery. These findings indicated that topical administration of GA is an alternative route for melanoma treatment.

Gambogic acid: A shining natural compound to nanomedicine for cancer therapeutics

The United States Food and Drug Administration has permitted number of therapeutic agents for cancer treatment. Most of them are expensive and have some degree of systemic toxicity which makes overbearing in clinical settings. Although advanced research continuously applied in cancer therapeutics, but drug resistance, metastasis, and recurrence remain unanswerable. These accounts to an urgent clinical need to discover natural compounds with precisely safe and highly efficient for the cancer prevention and cancer therapy. Gambogic acid (GA) is the principle bioactive and caged xanthone component, a brownish gamboge resin secreted from the of Garcinia hanburyi tree. This molecule showed a spectrum of biological and clinical benefits against various cancers. In this review, we document distinct biological characteristics of GA as a novel anti-cancer agent. This review also delineates specific molecular mechanism(s) of GA that are involved in anti-cancer, anti-metastasis, anti-angiogenesis, and chemo-/radiation sensitizer activities. Furthermore, recent evidence, development, and implementation of various nanoformulations of gambogic acid (nanomedicine) have been described.