Cucurbitacin B inhibits the stemness and metastatic abilities of NSCLC via downregulation of canonical Wnt/β-catenin signaling axis

Ziyuglycoside II, a triterpene glycoside compound in Sanguisorbae officinalis l. extract, suppresses metastasis in osteosarcoma via CBX4-mediated Wnt/β-catenin signal pathway

BACKGROUND

Osteosarcoma (OS), the most prevalent primary bone malignancy, exhibits rapid growth and a high tendency for lung metastasis, posing significant treatment challenges. Ziyuglycoside II (ZGS II), a main active compound derived from Sanguisorba officinalis l., has shown potential in cancer treatment. However, the effects of ZGS II and its potential mechanism in OS remain elusive.

PURPOSE

This study aims to explore the anti-metastatic potential of ZGS II in OS, offering a novel therapeutic strategy for improved patient outcomes.

METHODS

Cell viability and proliferation was detected by cell counting kit-8 (CCK-8) and clone formation assay, respectively. Transwell and wound-healing assay were applied to evaluate the potential metastatic abilities of OS cells in vitro. More critically, the chromobox protein homolog 4 (CBX4) and Wnt/β-catenin signaling pathway was investigated utilizing Western blotting, immunohistochemistry, shRNA knockdown and immunofluorescence. An orthotopic metastasis mouse model was utilized to evaluate the efficacy of ZGS II in suppressing OS metastasis in vivo, with molecular docking studies conducted to elucidate the interaction between ZGS II and the CBX4 protein.

RESULTS

Our study demonstrated the potent inhibitory effects of ZGS II on OS cell proliferation and induced apoptosis in vitro, as evidenced by decreased cell viability, enhanced caspase-3 activation, and mitochondrial dysfunction. Furthermore, using an orthotopic metastasis mouse model, we illustrated that ZGS II effectively suppressed tumor growth and lung metastasis in vivo. Notably, our investigation revealed that the antitumor action of ZGS II is dependent on the reduction of CBX4 levels, leading to the attenuation of the Wnt/β-catenin signaling pathway activation. Molecular docking analyses supported this pathway's suppression, showing that ZGS II has the capability to directly bind and disrupt CBX4 function. To further confirm this mechanism, we utilized shRNA to silence CBX4 in OS cells, which significantly enhanced the inhibitory impact of ZGS II on cell migration.

CONCLUSION

Our study findings reveal that ZGS II efficiently suppresses both metastasis and tumor growth in OS by a novel mechanism that entails the inhibition of the CBX4-regulated Wnt/β-catenin pathway. These outcomes highlight the promising potential of ZGS II as a therapeutic agent for managing metastatic OS, thus justifying the need for additional clinical investigations.

Notch Signaling Suppression by Golden Phytochemicals: Potential for Cancer Therapy

Cancer is one of the main causes of mortality worldwide. Cancer cells are characterized by unregulated cellular processes, including proliferation, progression, and angiogenesis. The occurrence of these processes is due to the dysregulation of various signaling pathways such as NF-κB (nuclear factor-κB), Wnt/beta-catenin, Notch signaling and MAPK (mitogen-activated protein kinases). Notch signaling pathways cause the progression of various types of malignant tumors. Among the phytochemicals for cancer therapy, several have attracted great interest, including curcumin, genistein, quercetin, silibinin, resveratrol, cucurbitacin and glycyrrhizin. Given the great cellular and molecular heterogeneity within tumors and the high toxicity and side effects of synthetic chemotherapeutics, natural products with pleiotropic effects that simultaneously target numerous signaling pathways appear to be ideal substitutes for cancer therapy. With this in mind, we take a look at the current status, impact and potential of known compounds as golden phytochemicals on key signaling pathways in tumors, focusing on the Notch pathway. This review may be useful for discovering new molecular targets for safe and efficient cancer therapy with natural chemotherapeutics.

Cucurbitacin-B inhibits cancer cell migration by targeting mortalin and HDM2: computational and in vitro experimental evidence

Cancer metastasis, a highly complex process wherein cancer cells move from the primary site to other sites in the body, is a major hurdle in its therapeutics. A large array of synthetic chemotherapeutic molecules used for the treatment of metastatic cancers, besides being extremely expensive and unaffordable, are known to cause severe adverse effects leading to poor quality of life (QOL) of the patients. In this premise, natural compounds (considered safe, easily available and economic) that possess the potential to inhibit migration of cancer cells are deemed useful and hence are on demand. Cucurbitacin-B (19-(10→9β)-abeo-10-lanost-5-ene triterpene, called Cuc-B) is a steroid mostly found in plants of Cucurbitaceae family. It has been shown to possess anticancer activity although the molecular mechanism remains poorly defined. We present evidence that Cuc-B has the ability to interact with mortalin and HDM2 proteins that are enriched in cancer cells, suppress wild type p53 function and promote cancer cell migration. Computational analyses showed that Cuc-B interacts with mortalin similar to MKT077 and Withanone, both have been shown to reactivate p53 function and inhibit cell migration. Furthermore, Cuc-B interacted with HDM2 similar to Y30, a well-known inhibitor of HDM2. Experimental cell and molecular analyses demonstrated the downregulation of several proteins, critically involved in cell migration in Cuc-B (low non-toxic doses)-treated cancer cells and exhibited inhibition of cell migration. The data suggested that Cuc-B is a potential natural drug that warrants further mechanistic and clinical studies for its use in the management of metastatic cancers.Communicated by Ramaswamy H. Sarma.

Modulation of hypoxia-inducible factor-1 signaling pathways in cancer angiogenesis, invasion, and metastasis by natural compounds: a comprehensive and critical review

Tumor cells employ multiple signaling mediators to escape the hypoxic condition and trigger angiogenesis and metastasis. As a critical orchestrate of tumorigenic conditions, hypoxia-inducible factor-1 (HIF-1) is responsible for stimulating several target genes and dysregulated pathways in tumor invasion and migration. Therefore, targeting HIF-1 pathway and cross-talked mediators seems to be a novel strategy in cancer prevention and treatment. In recent decades, tremendous efforts have been made to develop multi-targeted therapies to modulate several dysregulated pathways in cancer angiogenesis, invasion, and metastasis. In this line, natural compounds have shown a bright future in combating angiogenic and metastatic conditions. Among the natural secondary metabolites, we have evaluated the critical potential of phenolic compounds, terpenes/terpenoids, alkaloids, sulfur compounds, marine- and microbe-derived agents in the attenuation of HIF-1, and interconnected pathways in fighting tumor-associated angiogenesis and invasion. This is the first comprehensive review on natural constituents as potential regulators of HIF-1 and interconnected pathways against cancer angiogenesis and metastasis. This review aims to reshape the previous strategies in cancer prevention and treatment.

Navigating Tumour Microenvironment and Wnt Signalling Crosstalk: Implications for Advanced Cancer Therapeutics

Cancer therapeutics face significant challenges due to drug resistance and tumour recurrence. The tumour microenvironment (TME) is a crucial contributor and essential hallmark of cancer. It encompasses various components surrounding the tumour, including intercellular elements, immune system cells, the vascular system, stem cells, and extracellular matrices, all of which play critical roles in tumour progression, epithelial-mesenchymal transition, metastasis, drug resistance, and relapse. These components interact with multiple signalling pathways, positively or negatively influencing cell growth. Abnormal regulation of the Wnt signalling pathway has been observed in tumorigenesis and contributes to tumour growth. A comprehensive understanding and characterisation of how different cells within the TME communicate through signalling pathways is vital. This review aims to explore the intricate and dynamic interactions, expressions, and alterations of TME components and the Wnt signalling pathway, offering valuable insights into the development of therapeutic applications.

Potential of cucurbitacin as an anticancer drug

In Chinese medicine, the Cucurbitaceae family contains many compounds known as cucurbitacins, which have been categorized into 12 classes ranging from A to T and more than 200 derivatives. Cucurbitacins are a class of highly oxidized tetracyclic triterpenoids with potent anticancer properties. The eight components of cucurbitacins with the strongest anticancer activity are cucurbitacins B, D, E, I, IIa, L-glucoside, Q, and R. Cucurbitacins have also been reported to suppress JAK-STAT 3, mTOR, VEGFR, Wnt/β-catenin, and MAPK signaling pathways, all of which are crucial for the survival and demise of cancer cells. In this paper, we review the progress in research on cucurbitacin-induced apoptosis, autophagy, cytoskeleton disruption, cell cycle arrest, inhibition of cell proliferation, inhibition of invasion and migration, inhibition of angiogenesis, epigenetic alterations, and synergistic anticancer effects in tumor cells. Recent studies have identified cucurbitacins as promising molecules for therapeutic innovation with broad versatility in immune response. Thus, cucurbitacin is a promising class of anticancer agents that can be used alone or in combination with chemotherapy and radiotherapy for the treatment of many types of cancer.Therefore, based on the research reports in the past five years at home and abroad, we further summarize and review the structural characteristics, chemical and biological activities, and studies of cucurbitacins based on the previous studies to provide a reference for further development and utilization of cucurbitacins.

Natural compounds: Wnt pathway inhibitors with therapeutic potential in lung cancer

The Wnt/β-catenin pathway is abnormally activated in most lung cancer tissues and considered to be an accelerator of carcinogenesis and lung cancer progression, which is closely related to increased morbidity rates, malignant progression, and treatment resistance. Although targeting the canonical Wnt/β-catenin pathway shows significant potential for lung cancer therapy, it still faces challenges owing to its complexity, tumor heterogeneity and wide physiological activity. Therefore, it is necessary to elucidate the role of the abnormal activation of the Wnt/β-catenin pathway in lung cancer progression. Moreover, Wnt inhibitors used in lung cancer clinical trials are expected to break existing therapeutic patterns, although their adverse effects limit the treatment window. This is the first study to summarize the research progress on various compounds, including natural products and derivatives, that target the canonical Wnt pathway in lung cancer to develop safer and more targeted drugs or alternatives. Various natural products have been found to inhibit Wnt/β-catenin in various ways, such as through upstream and downstream intervention pathways, and have shown encouraging preclinical anti-tumor efficacy. Their diversity and low toxicity make them a popular research topic, laying the foundation for further combination therapies and drug development.

Extensive review on breast cancer its etiology, progression, prognostic markers, and treatment

As the most frequent and vulnerable malignancy among women, breast cancer universally manifests a formidable healthcare challenge. From a biological and molecular perspective, it is a heterogenous disease and is stratified based on the etiological factors driving breast carcinogenesis. Notably, genetic predispositions and epigenetic impacts often constitute the heterogeneity of this disease. Typically, breast cancer is classified intrinsically into histological subtypes in clinical landscapes. These stratifications empower physicians to tailor precise treatments among the spectrum of breast cancer therapeutics. In this pursuit, numerous prognostic algorithms are extensively characterized, drastically changing how breast cancer is portrayed. Therefore, it is a basic requisite to comprehend the multidisciplinary rationales of breast cancer to assist the evolution of novel therapeutic strategies. This review aims at highlighting the molecular and genetic grounds of cancer additionally with therapeutic and phytotherapeutic context. Substantially, it also renders researchers with an insight into the breast cancer cell lines as a model paradigm for breast cancer research interventions.

A Systematic Review of Progress toward Unlocking the Power of Epigenetics in NSCLC: Latest Updates and Perspectives

Epigenetic research has the potential to improve our understanding of the pathogenesis of cancer, specifically non-small-cell lung cancer, and support our efforts to personalize the management of the disease. Epigenetic alterations are expected to have relevance for early detection, diagnosis, outcome prediction, and tumor response to therapy. Additionally, epi-drugs as therapeutic modalities may lead to the recovery of genes delaying tumor growth, thus increasing survival rates, and may be effective against tumors without druggable mutations. Epigenetic changes involve DNA methylation, histone modifications, and the activity of non-coding RNAs, causing gene expression changes and their mutual interactions. This systematic review, based on 110 studies, gives a comprehensive overview of new perspectives on diagnostic (28 studies) and prognostic (25 studies) epigenetic biomarkers, as well as epigenetic treatment options (57 studies) for non-small-cell lung cancer. This paper outlines the crosstalk between epigenetic and genetic factors as well as elucidates clinical contexts including epigenetic treatments, such as dietary supplements and food additives, which serve as anti-carcinogenic compounds and regulators of cellular epigenetics and which are used to reduce toxicity. Furthermore, a future-oriented exploration of epigenetic studies in NSCLC is presented. The findings suggest that additional studies are necessary to comprehend the mechanisms of epigenetic changes and investigate biomarkers, response rates, and tailored combinations of treatments. In the future, epigenetics could have the potential to become an integral part of diagnostics, prognostics, and personalized treatment in NSCLC.

Cucurbitacin B: A review of its pharmacology, toxicity, and pharmacokinetics

Cucurbitacin B (CuB, C₃₂H₄₆O₈), the most abundant and active member of cucurbitacins, which are highly oxidized tetracyclic triterpenoids. Cucurbitacins are widely distributed in a variety of plants and mainly isolated from plants in the Cucurbitaceae family. CuB is mostly obtained from the pedicel of Cucumis melo L. Modern pharmacological studies have confirmed that CuB has a broad range of pharmacological activities, with significant therapeutic effects on a variety of diseases including inflammatory diseases, neurodegenerative diseases, diabetes mellitus, and cancers. In this study the PubMed, Web of Science, Science Direct, and China National Knowledge Infrastructure (CNKI) databases were searched from 1986 to 2022. After inclusion and exclusion criteria were applied, 98 out of 2484 articles were selected for a systematic review to comprehensively summarize the pharmacological activity, toxicity, and pharmacokinetic properties of CuB. The results showed that CuB exhibits potent anti-inflammatory, antioxidant, antiviral, hypoglycemic, hepatoprotective, neuroprotective, and anti-cancer activities mainly via regulating various signaling pathways, such as the Janus kinase/signal transducer and activator of transcription-3 (JAK/STAT3), nuclear factor erythroid 2-related factor-2/antioxidant responsive element (Nrf2/ARE), nuclear factor (NF)-κB, AMP-activated protein kinase (AMPK), mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)/Akt, cancerous inhibitor of protein phosphatase-2A/protein phosphatase-2A (CIP2A/PP2A), Wnt, focal adhesion kinase (FAK), Notch, and Hippo-Yes-associated protein (YAP) pathways. Studies of its toxicity and pharmacokinetic properties showed that CuB has non-specific toxicity and low bioavailability. In addition, derivatives and clinical applications of CuB are discussed in this paper.

Cucurbitacins as potential anticancer agents: new insights on molecular mechanisms

Since ancient times, plants have been an extensive reservoir of bioactive compounds with therapeutic interest for new drug development and clinical application. Cucurbitacins are a compelling example of these drug leads, primarily present in the plant kingdom, especially in the Cucurbitaceae family. However, these natural compounds are also known in several genera within other plant families. Beyond the Cucurbitaceae family, they are also present in other plant families, as well as in some fungi and one shell-less marine mollusc. Despite the natural abundance of cucurbitacins in different natural species, their obtaining and isolation is limited, as a result, an increase in their chemical synthesis has been developed by researchers. Data on cucurbitacins and their anticancer activities were collected from databases such as PubMed/MedLine, TRIP database, Web of Science, Google Scholar, and ScienceDirect and the information was arranged sequentially for a better understanding of the antitumor potential. The results of the studies showed that cucurbitacins have significant biological activities, such as anti-inflammatory, antioxidant, antimalarial, antimicrobial, hepatoprotective and antitumor potential. In conclusion, there are several studies, both in vitro and in vivo reporting this important anticancer/chemopreventive potential; hence a comprehensive review on this topic is recommended for future clinical research.

Prophylactic effects of cucurbitacin B in the EAE Model of multiple sclerosis by adjustment of STAT3/IL-23/IL-17 axis and improvement of neuropsychological symptoms

Multiple sclerosis (MS) is an autoimmune disease that affects the central nervous system. Although remarkable progress has been made in treating MS, current therapies are less effective in protecting against the progression of the disease. Since cucurbitacins have shown an extreme range of pharmacological properties, in this study, we aimed to investigate the prophylactic effect of cucurbitacin B (CuB) in the experimental MS model. Experimental autoimmune encephalomyelitis (EAE) induced by subcutaneous immunization of MOG35-55 in C57BL/6 mice. CuB interventions (0.5 and 1 mg/kg, i.p.) were performed every other day from the first day of EAE induction. Assessment of clinical scores and motor function, inflammatory responses, and microglial activation were assessed by qRT-PCR, western blotting, and immunohistochemical (IHC) analyses. CuB (1 mg/kg) significantly decreased the population of CD45⁺ (P < 0.01), CD11b⁺ (P < 0.01) and CD45⁺/CD11b⁺ (P < 0.05) cells in cortical lesions of EAE mice. In addition, activation of STAT3 (P < 0.001), expression of IL-17 A and IL-23 A (both mRNA and protein), and transcription of Iba-1 significantly decreased. On the contrary, CuB (1 mg/kg) significantly increased the transcription of MBP and Olig-2. Furthermore, a significant decrease in the severity of EAE (P < 0.05), and an improvement in motor function (P < 0.05) and coordination (P < 0.05) were observed after treatment with a high dose of CuB. Our results suggest that CuB may have a wide-ranging effect on autoimmune responses in MS via a reduction in STAT3 activation, microgliosis, and adaptation of the IL-23/IL-17 axis. Further studies are needed to investigate the exact effect of CuB in glial cells and its efficiency and bioavailability in other neuroinflammatory diseases.

Ivermectin inhibits tumor metastasis by regulating the Wnt/β-catenin/integrin β1/FAK signaling pathway

Tumor metastasis is the major cause of cancer mortality; therefore, it is imperative to discover effective therapeutic drugs for anti-metastasis therapy. In the current study, we investigated whether ivermectin (IVM), an FDA-approved antiparasitic drug, could prevent cancer metastasis. Colorectal and breast cancer cell lines and a cancer cell-derived xenograft tumor metastasis model were used to investigate the anti-metastasis effect of IVM. Our results showed that IVM significantly inhibited the motility of cancer cells in vitro and tumor metastasis in vivo. Mechanistically, IVM suppressed the expressions of the migration-related proteins via inhibiting the activation of Wnt/β-catenin/integrin β1/FAK and the downstream signaling cascades. Our findings indicated that IVM was capable of suppressing tumor metastasis, which provided the rationale on exploring the potential clinical application of IVM in the prevention and treatment of cancer metastasis.

Mahanimbine isolated from Murraya koenigii inhibits P-glycoprotein involved in lung cancer chemoresistance

P-glycoprotein (P-gp), a transmembrane glycoprotein, is mainly involved in lung cancer multidrug resistance. Several P-gp inhibitors have been developed to enhance the efficacy of chemotherapeutics and overcome drug resistance. However, most of them failed in the clinical stages due to undesirable side effects. Therefore, there is a requirement to develop P-gp inhibitors from natural sources. Dietary spice bioactives have been well-known for their anticancer activities. However, their role in modulating the P-gp activity has not been well investigated. Therefore, we have screened for the potential bioactives from various spice plants with P-gp modulatory activity using computational molecular docking analysis. The computational analysis revealed several key bioactives from curry leaves, specifically mahanimbine, exhibited a strong binding affinity with P-gp. Unfortunately, mahanimbine is available with few commercial sources at very high prices. Therefore, we prepared a curry leaves extract and isolated mahanimbine by a novel, yet simple, extraction method that requires less time and causes minimum environmental hazards. After purification, structure, and mass were confirmed for the isolated compound by IR spectrum and LC-MS/MS analysis, respectively. In the mechanistic study, hydrolysis of ATP and substrate efflux by P-gp are coupled. Hence, ATP binding at the ATPase-binding site is one of the fundamental steps for the P-gp efflux cycle. We found that mahanimbine demonstrated to stimulate P-gp ATPase activity. Concurrently, it enhanced the intracellular accumulation of P-gp substrates Rhodamine 123 and Hoechst stain, which indicates that mahanimbine modulates the function of P-gp. In addition, we have analyzed the complementary effect of mahanimbine with the chemotherapeutic drug gefitinib. We found that mahanimbine synergistically enhanced gefitinib efficiency by increasing its intracellular accumulation in lung cancer cells. Overall, mahanimbine has been shown to be a potent P-gp modulator. Therefore, mahanimbine can be further developed as a potential candidate to overcome chemoresistance in lung cancer.

Extract of Murraya koenigii selectively causes genomic instability by altering redox-status via targeting PI3K/AKT/Nrf2/caspase-3 signaling pathway in human non-small cell lung cancer

BACKGROUND

Lung cancer is the leading cause of cancer-related death worldwide. Dietary bioactives have been used as alternative therapeutics to overcome various adverse effects caused by chemotherapeutics. Curry leaves are a widely used culinary spice and different parts of this plant have been used in traditional medicines. Curry leaves are a rich source of multiple bioactives, especially polyphenols and alkaloids. Therefore, extraction processes play a key role in obtaining the optimum yield of bioactives and their efficacy.

PURPOSE

We aim to select an extraction process that achieves the optimum yield of bioactives in curry leaves crude extract (CLCE) with minimum solvent usage and in a shorter time. Further, to investigate the anticancer properties of CLCE and its mechanism against lung cancer.

METHODS

Different extraction processes were performed and analyzed polyphenol content. The bioactives and essential oils present in curry leaves were identified through LC-MS/MS and GC-MS analysis. The cytotoxicity of microwave-assisted CLCE (MA-CLCE) was investigated through MTT and colony-forming assays. The DNA damage was observed by comet assay. The apoptotic mechanisms of MA-CLCE were investigated by estimating ROS production, depolarization of mitochondrial membrane potential (MMP), and apoptotic proteins. The glutathione assay estimated the antioxidant potential of MA-CLCE in normal cells.

RESULTS

Generally, conventional extraction methods require high temperatures, extra energy input, and time. Recently, green extraction processes are getting wider attention as alternative extraction methods. This study compared different extraction processes and found that the microwave-assisted extraction (MAE) method yields the highest polyphenols from curry leaves among other extraction processes with minimum processing. The MA-CLCE functions as an antioxidant under normal physiological conditions but pro-oxidant to cancer cells. MA-CLCE scavenges free radicals and enhances the intracellular GSH level in alveolar macrophages in situ. We found that MA-CLCE selectively inhibits cell proliferation and induces apoptosis in cancer cells by altering cellular redox status. MA-CLCE induces chromatin condensation and genotoxicity through ROS-induced depolarization of MMP. The depolarization of MMP causes the release of cytochrome c into the cytosol and activates the apoptotic pathway in lung cancer cells. However, pretreatment with ascorbic acid, an antioxidant, inhibits the MA-CLCE-induced apoptosis by reducing ROS production, which impedes mitochondrial membrane disruption, preventing BAX/BCL-2 expression alteration. Simultaneously, MA-CLCE downregulates the expression of survival signaling regulator PI3K/AKT, which modulates Nrf-2. MA-CLCE also diminishes intracellular antioxidant proficiency by suppressing Nrf-2 expression, followed by HO-1 expressions.

CONCLUSION

Among several extraction methods, MA-CLCE is rich in several bioactives, especially polyphenols, alkaloids, and essential oils. Here, we reported for the first time that MA-CLCE functions as a pro-oxidant to lung cancer cells and acts as an antioxidant to normal cells by regulating different cellular programs and signaling pathways. Therefore, it can be further developed as a promising phytomedicine against lung cancer.

Kaempferol and Apigenin suppresses the stemness properties of TNBC cells by modulating Sirtuins

Sirtuins (SIRTs) overexpression serves as a potential therapeutic target for TNBC because it is associated with bioactivities of cancer stem cells (CSCs), resistance to chemotherapy, and metastasis. Irrespective of the availability of synthetic SIRT inhibitors, new SIRT inhibitors with enhanced potency and lesser side effects serve as current unmet needs. Therefore, bioactive dietary compounds; kaempferol (KMP) and apigenin (API) were investigated for their anti-SIRTs potential. We observed KMP and API inhibits cellular proliferation by DNA damage and S-phase cell cycle arrest in TNBC Cells. They also suppress stemness properties in TNBCs as observed in experiments of mammosphere formation and clonogenic potential. Our mechanistic approach indicated that KMP and API inhibited SIRT3 and SIRT6 proteins, as evidenced by our in silico and in vitro experiment. Collectively, our studies suggest that KMP and API are promising candidates to be further developed as sirtuin modulators against TNBCs.

Cucurbitacins: Nature’s Wonder Molecules

Abstract:

Over the past decades, several natural constituents belonging to different classes have been isolated from plants for medicinal purposes. Cucurbitacins is one such type of natural compound. Cucurbitacin is any of a class of biochemical compounds that some plants notably members of the pumpkin and gourd family, Cucurbitaceae produce and which function as a defense against herbivores. They and their derivatives have been found in many plant families (including Brassicaceae, Cucurbitaceae, Scrophulariaceae, Begoniaceae, Elaeocarpaceae, Datiscaceae, Desfontainiaceae, Polemoniaceae, Primulaceae, Rubiaceae, Sterculiaceae, Rosaceae, and Thymelaeaceae), in some mushrooms (including Russula and Hebeloma) and even in some marine mollusks. They have been isolated from various plant species, chiefly belonging to the Cucurbitaceae family which comprises around 130 genera and 800 species. Cucurbitacins are a group of tetracyclic triterpenoid substances that are highly oxygenated and contain a cucurbitane skeleton characterized by 9β-methyl−19-norlanosta-5-ene. Cucurbitacins can be categorized into twelve main groups according to variations in their side-chains. Cucurbitacins A, B, C, D, E, F, I, J, K, L, O, P, Q, R, S, and their glycosides are mainly found in Cucurbitaceae family members. These plants have been used as folk medicines in some countries because of their broad spectrum of crucial pharmacological activities such as anti-inflammatory, anti-cancer, anti-diabetic, and anti-atherosclerotic effects. The present review explores the possibility of a correlation between the chemistry of various Cucurbitacins and the uses of the plants which contain them, thereby opening avenues for further phytochemical, ethnomedicinal, and modern pharmacological research on these important molecules.

The Effect of Terpenoid Natural Chinese Medicine Molecular Compound on Lung Cancer Treatment

Among all malignant tumors in the whole universe, the incidence and mortality of lung cancer disease rank first. Especially in the past few years, the occurrence of lung cancer in the urban population has continued to increase, which seriously threatens the lives and health of people. Among the many treatments for lung cancer, chemotherapy is the best one, but traditional chemotherapy has low specificity and drug resistance. To address the above issue, this study reviews the five biological pathways that common terpenoid compounds in medicinal plants interfere with the occurrence and development of lung cancer: cell proliferation, cell apoptosis, cell autophagy, cell invasion, metastasis, and immune mechanism regulation. In addition, the mechanism of the terpenoid natural traditional Chinese medicine monomer compound combined with Western medicine in the multipathway antilung cancer is summarized.

Cucurbitacin B enhances apoptosis in gefitinib resistant non‑small cell lung cancer by modulating the miR‑17‑5p/STAT3 axis

Tyrosine kinase inhibitors, such as gefitinib, are currently widely used as targeted therapeutics for non-small cell lung cancer (NSCLC). Although drug resistance has become a major obstacle to successful treatment, mechanisms underlying resistance to gefitinib remain unclear. Therefore, the present study aimed to investigate the impact of adjunctive cucurbitacin B (CuB) on gefitinib resistance (GR) in the PC9 cell line, including identifying underlying mechanisms. Reverse transcription-quantitative PCR demonstrated significant downregulation of microRNA (miR)-17-5p expression in GR PC9 cells (PC9/GR), and this could be reversed by CuB. During combination treatment with CuB and gefitinib at IC₂₅, PC9/GR cell proliferation was downregulated, and apoptosis was upregulated. The presence of a miR-17-5p inhibitor negated the effects of CuB and gefitinib, whereas the presence of a miR-17-5p mimic enhanced them. Luciferase assays demonstrated that the hypothetical target gene, signal transducer and activator of transcription 3 (STAT3), was directly targeted by miR-17-5p. Moreover, significant elevation of the STAT3 protein and phosphorylation levels in PC9/GR cells was reversed by the addition of CuB, despite a lack of change in STAT3 transcription level. During combined treatment with CuB and gefitinib at IC₂₅, the STAT3 protein expression was negatively associated with the expression of miR-17-5p. Overexpression of STAT3 increased proliferation and decreased apoptosis and the protein levels of apoptosis-related factors cleaved caspase-3 and cleaved caspase-9 of PC9/GR cells. Findings indicated that STAT3 protein and phosphorylation levels became elevated in response to gefitinib, and that CuB-induced miR-17-5p expression led to STAT3 degradation, thereby ameliorating GR. In summary, CuB reduced the proliferation of GR PC9 cells by modulating the miR-17-5p/STAT3 axis, and may represent a promising potential novel strategy for the reversal of GR.

Use of cucurbitacins for lung cancer research and therapy

As the main substance in some traditional Chinese medicines, cucurbitacins have been used to treat hepatitis for decades in China. Currently, the use of cucurbitacins against cancer and other diseases has achieved towering popularity among researchers worldwide, as detailed in this review with summarized tables. Numerous studies have reported the potential tumor-killing activities of cucurbitacins in multiple aspects of human malignancies. Continuous research on its anticancer activity mechanisms also brings a glimmer of light to the treatment of patients with lung cancer. In line with the promising roles of cucurbitacins against cancer, through various molecular signaling pathways, it is justifiable to propose the use of cucurbitacins as a potential mainline chemotherapy before the onset and after the diagnosis of lung cancers. Here, this article mainly summarized the findings about the biological functions and underlying mechanisms of cucurbitacins on lung cancer pathogenesis and treatment. In addition, we also discussed the safety and efficacy of their application for further research and even clinical practice.

Piperine and Celecoxib synergistically inhibit colon cancer cell proliferation via modulating Wnt/β-catenin signaling pathway

BACKGROUND

Celecoxib (CXB), a selective COX-2 inhibitor NSAID, has exhibited prominent anti-proliferative potential against numerous cancers. However, its low bioavailability and long term exposure related cardiovascular side effects, limit its clinical application. In order to overcome these limitations, natural bioactive compounds with lower toxicity profile are used in combination with therapeutic drugs. Therfore, in this study Piperine (PIP), a natural chemo-preventive agent possessing drug bioavailability enhancing properties, was considered to be used in combination with low doses of CXB.

PURPOSE

We hypothesized that the combination of PIP with CXB will have a synergistic anti-proliferative effect on colon cancer cells.

STUDY DESIGN

The potency of PIP and CXB alone and in combination was evaluated in HT-29 human colon adenocarcinoma cells and mechanism of growth inhibition was investigated by analyzing the players in apoptotic and Wnt/β-catenin signaling pathways.

METHODS

The effect of PIP on the oral bioavailability of CXB in mice was investigated using HPLC analysis. The study investigated the synergistic anti-proliferative effect of CXB and PIP on HT-29 cells and IEC-6 non-tumorigenic rat intestinal epithelial cells by SRB cell viability assay. Further, the cellular and molecular mechanism(s) involved in the anti-proliferative combinatorial effect was extensively explored in HT-29 cells by flow cytometry and western blotting. The in vivo efficacy of this combination was studied in CT26.WT tumor syngeneic Balb/c mice model.

RESULTS

PIP as a bioenhancer increased the oral bioavailability of CXB (129%). The IC50 of CXB and PIP were evaluated to select doses for combination treatment of HT-29 cells. The drug combinations having combination index (CI) less than 1 were screened using CompuSyn software. These combinations were significantly cytotoxic to HT-29 cells but IEC-6 were least effected. Further, the mechanism behind CXB and PIP mediated cell death was explored. The co-treatment led to reactive oxygen species generation, mitochondrial dysfunction, caspase activation and enhanced apoptosis in HT-29 cells. Additionally, the combination treatment synergistically modulated Wnt/β-catenin pathway, downregulated the stemness markers and boosted therapeutic response in CT26 syngeneic Balb/c mice.

CONCLUSION

The outcomes of the study suggests that combining CXB and PIP offers a novel approach for the treatment of colon cancer.

The role of hypoxia in the tumor microenvironment and development of cancer stem cell: a novel approach to developing treatment

Hypoxia is a common feature of solid tumors, and develops because of the rapid growth of the tumor that outstrips the oxygen supply, and impaired blood flow due to the formation of abnormal blood vessels supplying the tumor. It has been reported that tumor hypoxia can: activate angiogenesis, thereby enhancing invasiveness and risk of metastasis; increase survival of tumor, as well as suppress anti-tumor immunity and hamper the therapeutic response. Hypoxia mediates these effects by several potential mechanisms: altering gene expression, the activation of oncogenes, inactivation of suppressor genes, reducing genomic stability and clonal selection. We have reviewed the effects of hypoxia on tumor biology and the possible strategiesto manage the hypoxic tumor microenvironment (TME), highlighting the potential use of cancer stem cells in tumor treatment.

Cucurbitacin mediated regulation of deregulated oncogenic signaling cascades and non-coding RNAs in different cancers: Spotlight on JAK/STAT, Wnt/β-catenin, mTOR, TRAIL-mediated pathways

Research over decades has enabled us in developing a better understanding of the multifaceted and heterogeneous nature of cancer. High-throughput technologies have helped the researchers in unraveling of the underlying mechanisms which centrally regulate cancer onset, metastasis and drug resistance. Our rapidly expanding knowledge about signal transduction cascade has added another layer of complexity to already complicated nature of cancer. Deregulation of cell signaling pathways played a linchpin role in carcinogenesis and metastasis. Cucurbitacins have gained tremendous attention because of their remarkable pharmacological properties and considerable ability to mechanistically modulate myriad of cell signaling pathways in different cancers. In this review, we have attempted to provide a mechanistic and comprehensive analysis of regulation of oncogenic pathways by cucurbitacins in different cancers. We have partitioned this review into separate sections for exclusive analysis of each signaling pathway and critical assessment of the knowledge gaps. In this review, we will summarize most recent and landmark developments related to regulation of Wnt/β-catenin, JAK/STAT, mTOR, VEGFR, EGFR and Hippo pathway by cucurbitacins. Moreover, we will also address how cucurbitacins regulate DNA damage repair pathway and TRAIL-driven signaling in various cancers. However, there are still outstanding questions related to regulation of SHH/GLI, TGF/SMAD and Notch-driven pathway by cucurbitacins in different cancers. Future studies must converge on the analysis of full-fledge potential of cucurbitacins by in-depth analysis of these pathways and how these pathways can be therapeutically targeted by cucurbitacins.

Targeting β-tubulin/CCT-β complex induces apoptosis and suppresses migration and invasion of highly metastatic lung adenocarcinoma

Metastasis, the movement of cancer cells from one site to another, is responsible for the highest number of cancer deaths, especially in lung cancer patients. In this study, we first identified a prognostic marker of lung adenocarcinoma, TCP-1 β subunit (chaperonin-containing TCP-1β; CCT-β). We showed a compound that disrupted the interaction of CCT-β with β-tubulin killed a highly metastatic non-small cell lung cancer cell line CL1-5 through inducing Endoplasmic reticulum stress and caspases activation. Moreover, at the dosage of EC20, the compound inhibited migration and invasion of the lung cancer cells by suppressing matrix metalloproteinase (MMP)-2/9 and epithelial-mesenchymal transition (EMT)-related proteins through downregulating mitogen-activated protein kinases (MAPKs), Akt/β-catenin and integrin-focal adhesion kinase signaling pathways. Unlike the anticancer drugs, such as Taxol, that target the adenosine triphosphate site of β-tubulin, this study reveals a therapeutic target, β-tubulin/CCT-β complex, for metastatic human lung adenocarcinoma. The study demonstrated CCT-β as a prognostic marker. Targeting β-tubulin/CCT-β complex caused apoptosis and inhibited invasion/migration of CCT-β overexpressed, highly metastatic lung adenocarcinoma.

Negative Effect of Reduced NME1 Expression on Recurrence-Free Survival in Early Stage Non-Small Cell Lung Cancer

This study aimed to understand whether the effect of non-metastatic cells 1 (NME1) on recurrence-free survival (RFS) in early stage non-small cell lung cancer (NSCLC) can be modified by β-catenin overexpression and cisplatin-based adjuvant chemotherapy. Expression levels of NME1 and β-catenin were analyzed using immunohistochemistry in formalin-fixed paraffin-embedded tissues from 425 early stage NSCLC patients. Reduced NME1 expression was found in 39% of samples. The median duration of follow-up was 56 months, and recurrence was found in 186 (44%) of 425 patients. The negative effect of reduced NME1 expression on RFS was worsened by cisplatin-based adjuvant chemotherapy (adjusted hazard ratio = 3.26, 95% CI = 1.16–9.17, p = 0.03). β-catenin overexpression exacerbated the effect of reduced NME1 expression on RFS and the negative effect was greater when receiving cisplatin-based adjuvant chemotherapy: among patients treated with cisplatin-based adjuvant chemotherapy, hazard ratios of patients with reduced NME1 expression increased from 5.59 (95% confidence interval (CI) = 0.62–50.91, p = 0.13) to 15.52 (95% CI = 2.94–82.38, p = 0.001) by β-catenin overexpression, after adjusting for confounding factors. In conclusion, the present study suggests that cisplatin-based adjuvant chemotherapy needs to be carefully applied to early stage NSCLC patients with overexpressed β-catenin in combination with reduced NME1 expression.

Cancer Stem Cells: Acquisition, Characteristics, Therapeutic Implications, Targeting Strategies and Future Prospects

Since last two decades, the major cancer research has focused on understanding the characteristic properties and mechanism of formation of Cancer stem cells (CSCs), due to their ability to initiate tumor growth, self-renewal property and multi-drug resistance. The discovery of the mechanism of acquisition of stem-like properties by carcinoma cells via epithelial-mesenchymal transition (EMT) has paved a way towards a deeper understanding of CSCs and presented a possible avenue for the development of therapeutic strategies. In spite of years of research, various challenges, such as identification of CSC subpopulation, lack of appropriate experimental models, targeting cancer cells and CSCs specifically without harming normal cells, are being faced while dealing with CSCs. Here, we discuss the biology and characteristics of CSCs, mode of acquisition of stemness (via EMT) and development of multi-drug resistance, the role of tumor niche, the process of dissemination and metastasis, therapeutic implications of CSCs and necessity of targeting them. We emphasise various strategies being developed to specifically target CSCs, including those targeting biomarkers, key pathways and microenvironment. Finally, we focus on the challenges that need to be subdued and propose the aspects that need to be addressed in future studies in order to broaden the understanding of CSCs and develop novel strategies to eradicate them in clinical applications. Graphical Abstract Cancer Stem Cells(CSCs) have gained much attention in the last few decades due to their ability to initiate tumor growth and, self-renewal property and multi-drug resistance. Here, we represent the CSC model of cancer, Characteristics of CSCs, acquisition of stemness and metastatic dissemination of cancer, Therapeutic implications of CSCs and Various strategies being employed to target and eradicate CSCs.

Mannose Suppresses the Proliferation and Metastasis of Lung Cancer by Targeting the ERK/GSK-3β/β-Catenin/SNAIL Axis

INTRODUCTION

It has been found that mannose exerts antitumoural properties in vitro and in animal models. Whether mannose has potential anti-proliferative and anti-metastatic properties against non-small-cell lung cancer (NSCLC) is still unclear.

METHODS

Here, we performed ex vivo experiments and established a nude mouse model to evaluate the anticancer effects of mannose on NSCLC cells and its effects on the ERK/GSK-3β/β-catenin/SNAIL axis. A CCK-8 assay was conducted to evaluate the effects of mannose on lung cancer cells (A549 and HCC827) and normal lung cells (HPAEpiC). Transwells were used to examine the motility of cancer cells. qRT-PCR was used to evaluate the effects of mannose on the mRNA expression of β-catenin. Western blotting was conducted to explore the effects of mannose on the ERK/GSK-3β/β-catenin/SNAIL axis and nuclear accumulation of β-catenin. An animal model was established to evaluate the antitumoural effect of mannose on hepatic metastasis in vivo.

RESULTS

In this study, we found that mannose inhibited the proliferation of A549 and HCC827 cells in vitro both time- and dose-dependently. However, it exerted only a slight influence on the viability of normal lung cells in vitro. Moreover, mannose also inhibited the migrating and invading capacity of NSCLC cells in vitro. Using Western blotting, we observed that mannose reduced SNAIL and β-catenin expression and ERK activation and promoted phospho-GSK-3β expression. The ERK agonist LM22B-10 promoted the metastatic ability of NSCLC cells and increased SNAIL and β-catenin expression in cancer cells, which could be reversed by mannose. Furthermore, ERK-mediated phosphorylation of the β-catenin-Tyr654 residue might participate in the nuclear accumulation of β-catenin and its transcriptional function. The results from animal experiments showed that mannose effectively reduced hepatic metastasis of A549 cells in vivo. Furthermore, mannose inhibited ERK/GSK-3β/β-catenin/SNAIL in tumour tissues obtained from nude mice.

DISCUSSION

Collectively, these findings suggest that mannose exerts anti-metastatic activity against NSCLC by inhibiting the activation of the ERK/GSK-3β/β-catenin/SNAIL axis, which indicates the potential anticancer effects of mannose.

Cucurbitacin B and I inhibits colon cancer growth by targeting the Notch signaling pathway

Cancer stem cells (CSCs) have the ability to self-renew and induce drug resistance and recurrence in colorectal cancer (CRC). As current chemotherapy doesn’t eliminate CSCs completely, there is a need to identify novel agents to target them. We investigated the effects of cucurbitacin B (C-B) or I (C-I), a natural compound that exists in edible plants (bitter melons, cucumbers, pumpkins and zucchini), against CRC. C-B or C-I inhibited proliferation, clonogenicity, induced G₂/M cell-cycle arrest and caspase-mediated-apoptosis of CRC cells. C-B or C-I suppressed colonosphere formation and inhibited expression of CD44, DCLK1 and LGR5. These compounds inhibited notch signaling by reducing the expression of Notch 1–4 receptors, their ligands (Jagged 1-2, DLL1,3,4), γ-secretase complex proteins (Presenilin 1, Nicastrin), and downstream target Hes-1. Molecular docking showed that C-B or C-I binds to the ankyrin domain of Notch receptor, which was confirmed using the cellular thermal shift assay. Finally, C-B or C-I inhibited tumor xenograft growth in nude mice and decreased the expression of CSC-markers and notch signaling proteins in tumor tissues. Together, our study suggests that C-B and C-I inhibit colon cancer growth by inhibiting Notch signaling pathway.

In Vitro and In Vivo Antitumor Activity of Cucurbitacin C, a Novel Natural Product From Cucumber

Cucurbitacin C (CuC), a novel analogue of triterpenoids cucurbitacins, confers a bitter taste in cucumber. Genes and signaling pathways responsive for biosynthesis of CuC have been identified in the recent years. In the present study, we explored the anti-cancer effects of CuC against human cancers in vitro and in vivo. CuC inhibited proliferation and clonogenic potential of multiple cancer cells in a dose-dependent manner. Low-dose CuC treatment induced cell cycle arrest at G1 or G2/M stage in different cancer lines, whereas high-dose treatment of CuC caused apoptosis in cancer cells. PI3K-Akt signaling pathway was found to be one of the major pathways involved in CuC-induced cell growth arrest and apoptosis by RNA-Seq and Western blotting. Mechanistic dissection further confirmed that CuC effectively inhibited the Akt signaling by inhibition of Akt phosphorylation at Ser473. In vivo CuC treatment (0.1 mg/kg body weight) effectively inhibited growth of cancer cell-derived xenograft tumors in athymic nude mice and caused significant apoptosis. Our findings for the first time demonstrated the potential therapeutic significance of CuC against human cancers.

Naturally occurring anti-cancer compounds: shining from Chinese herbal medicine

Numerous natural products originated from Chinese herbal medicine exhibit anti-cancer activities, including anti-proliferative, pro-apoptotic, anti-metastatic, anti-angiogenic effects, as well as regulate autophagy, reverse multidrug resistance, balance immunity, and enhance chemotherapy in vitro and in vivo. To provide new insights into the critical path ahead, we systemically reviewed the most recent advances (reported since 2011) on the key compounds with anti-cancer effects derived from Chinese herbal medicine (curcumin, epigallocatechin gallate, berberine, artemisinin, ginsenoside Rg3, ursolic acid, silibinin, emodin, triptolide, cucurbitacin B, tanshinone I, oridonin, shikonin, gambogic acid, artesunate, wogonin, β-elemene, and cepharanthine) in scientific databases (PubMed, Web of Science, Medline, Scopus, and Clinical Trials). With a broader perspective, we focused on their recently discovered and/or investigated pharmacological effects, novel mechanism of action, relevant clinical studies, and their innovative applications in combined therapy and immunomodulation. In addition, the present review has extended to describe other promising compounds including dihydroartemisinin, ginsenoside Rh2, compound K, cucurbitacins D, E, I, tanshinone IIA and cryptotanshinone in view of their potentials in cancer therapy. Up to now, the evidence about the immunomodulatory effects and clinical trials of natural anti-cancer compounds from Chinese herbal medicine is very limited, and further research is needed to monitor their immunoregulatory effects and explore their mechanisms of action as modulators of immune checkpoints.

Interaction between laminin-5γ2 and integrin β1 promotes the tumor budding of colorectal cancer via the activation of Yes-associated proteins

Colorectal cancer (CRC) is a common cancer type and a threat to human health. Tumor budding (TB) is the presence of a single cancer cell or clusters of up to five cancer cells prior to the invasive front of an aggressive carcinoma and is an independent prognosis factor for CRC. The molecular mechanism of TB is still unclear, and drugs that inhibit this process are still in the blank stage. This study found that TBs exhibit characteristics of partial EMT with a decreased expression of E-cadherin and no substantial differences in the expression of N-cadherin and vimentin. We also observed the interaction of integrin with extracellular matrix components, laminin-5γ2 (LN-5γ2), play essential roles in the TB of CRC. We then verified that the interaction between LN-5γ2 and integrin β1 promotes the TB of CRC via the activation of FAK and Yes-associated proteins (YAP). A natural drug monomer, cucurbitacin B, was screened using virtual screening methods for the interaction interface of proteins. We found that this monomer could block the interaction interface between LN-5γ2 and integrin β1 and substantially inhibit the TB of CRC cells via inactivation of YAP. This study provides new insights into the mechanism of TB mechanism and the development of drugs targeting the TB of CRC.

Role of Phytochemicals in Cancer Prevention

The use of synthetic, natural, or biological agents to minimize the occurrence of cancer in healthy individuals is defined as cancer chemoprevention. Chemopreventive agents inhibit the development of cancer either by impeding DNA damage, which leads to malignancy or by reversing or blocking the division of premalignant cells with DNA damage. The benefit of this approach has been demonstrated in clinical trials of breast, prostate, and colon cancer. The continuous increase in cancer cases, failure of conventional chemotherapies to control cancer, and excessive toxicity of chemotherapies clearly demand an alternative approach. The first trial to show benefit of chemoprevention was undertaken in breast cancer patients with the use of tamoxifen, which demonstrated a significant decrease in invasive breast cancer. The success of using chemopreventive agents for protecting the high risk populations from cancer indicates that the strategy is rational and promising. Dietary components such as capsaicin, cucurbitacin B, isoflavones, catechins, lycopenes, benzyl isothiocyanate, phenethyl isothiocyanate, and piperlongumine have demonstrated inhibitory effects on cancer cells indicating that they may serve as chemopreventive agents. In this review, we have addressed the mechanism of chemopreventive and anticancer effects of several natural agents.

The Anticancer Efficiency of Citrullus colocynthis Toward the Colorectal Cancer Therapy

BACKGROUND

Colorectal cancer (CRC) remains a major cause of death worldwide. Chemotherapy is associated with some side effects during CRC treatment. Hence, proper employment of lower toxic and approaches exerting lowest side effects are essential. The Citrullus colocynthis (C. colocynthis) seems a potential anticancerous herbal medicine (HM) against CRC mostly via various efficient compounds.

METHODS

We performed a literature review regarding the anticancer traits of C. colocynthis against CRC. The possible active compounds, mechanisms, and combination therapies in vitro and in vivo or clinical trials have been also stated where found.

RESULTS AND CONCLUSION

The anticancerous effects of C. colocynthis has been via a variety of pathways including apoptotic pathways (increase in caspase-3 and inhibiting STAT3 function), antioxidant and anti-inflammatory (TNF-α, nitric oxide, and pro-inflammatory cytokines such as IL-6, IL-8, and IL-1α) traits, inhibition of Wnt/β-catenin signaling pathway, and antiangiogenesis and antimetastatic effects. Future studies will be promising regarding proper application of C. colocynthis compounds following their extraction.

Negative regulators of Wnt signaling in non-small cell lung cancer: Theoretical basis and therapeutic potency

Significant advances in the treatment of non-small cell lung cancer (NSCLC) have been made over the past decade, and they predominantly involve molecular targets such as epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements. However, despite the initial good response, drug resistance eventually develops. The Wnt signaling pathway has recently been considered important in embryonic development and tumorigenesis in many cancers, particularly NSCLC. Moreover, the aberrant Wnt pathway plays a significant role in NSCLC and is associated with cancer cell proliferation, metastasis, invasion and drug resistance, and the suppression of canonical or noncanonical Wnt signaling through various biological or pharmacological negative regulators has been proven to produce specific anticancer effects. Thus, blocking the Wnt pathway via its negative regulators may overcome the resistance of current treatment methods and lead to new treatment strategies for NSCLC. Therefore, in this review, we summarize recent studies on the role of negative regulators in Wnt signaling in NSCLC and the therapeutic potency of these molecules as agents and targets for NSCLC treatments.

Knockdown of YAP inhibits growth in Hep-2 laryngeal cancer cells via epithelial-mesenchymal transition and the Wnt/β-catenin pathway

BACKGROUND

Yes-associated protein (YAP) plays a crucial role in tumour development and it is the main effector of the Hippo signalling pathway. However, the mechanism underlying YAP downregulation in laryngeal cancer is still unclear. In our previous study, we found that YAP, compared with adjacent tissues, was expressed higher in laryngeal cancer and was also closely associated with histological differentiation, TNM stage and poor prognosis.

METHODS

In this study, we attempted to determine whether silenced YAP could downregulate human laryngeal carcinoma Hep-2 cells progression. YAP was downregulated in Hep-2 cells by shRNA, and the malignant ability of Hep-2 was assessed in vitro and in vivo.

RESULTS

In vitro, CCK-8, colony formation and wound healing assays showed that downregulation of YAP significantly reduced the rates of proliferation, migration, and invasion in Hep-2 cells. Downregulation of YAP distinctly induced G2/M cycle arrest and increased the rate of apoptosis. Accordingly, western blot assay suggested that the expression of DKK1, vimentin and β-catenin was significantly decreased after YAP downregulated treatment, thereby indicating that YAP mediated the EMT programme and the Wnt/β-catenin signalling pathway in carcinoma of the larynx. Furthermore, silencing of YAP suppressed Hep-2 cell tumourigenesis and metastasis in vivo.

CONCLUSION

In summary, our findings demonstrated the proliferation of YAP downregulation and the invasion of Hep-2 cells via downregulating the Wnt/β-catenin pathway in vitro and in vivo, suggesting that YAP may provide a potential therapeutic strategy for the treatment of laryngeal cancer.

Cucurbitacins extracted from Cucumis melo L. (CuEC) exert a hypotensive effect via regulating vascular tone

As an effective medicine for jaundice in traditional Chinese medicine, Cucumis melo L. has been widely used in China. However, its effect on vascular function is still unclear. In this study, we extracted the compounds of Cucumis melo L., and the major ingredients were identified as cucurbitacins (CuEC, cucurbitacins extracted from Cucumis melo L.), especially cucurbitacin B. We replicated the toxicity in mice by intraperitoneal injection of a high dose of CuEC (2 mg/kg) and demonstrated that the cause of death was CuEC-induced impairment of the endothelial barrier and, thus, increased vascular permeability via decreasing VE-cadherin conjunction. The administration of low doses of CuEC (1 mg/kg) led to a decline in systolic blood pressure (SBP) without causing toxicity in mice. More importantly, CuEC dramatically suppressed angiotensin II (Ang II)-induced SBP increase. Further studies demonstrated that CuEC facilitated acetylcholine-mediated vasodilation in mesenteric arteries of mice. In vitro studies showed that CuEC induced vasodilation in a dose-dependent manner in mesenteric arteries of both mice and rats. Pretreatment with CuEC inhibited phenylephrine-mediated vasoconstriction. In summary, a moderate dose of CuEC reduced SBP by improving blood vessel tension. Therefore, our study provides new experimental evidence for developing new antihypertensive drugs.

Cucurbitacin B Induces the Lysosomal Degradation of EGFR and Suppresses the CIP2A/PP2A/Akt Signaling Axis in Gefitinib-Resistant Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) patients carrying an epidermal growth factor receptor (EGFR) mutation are initially sensitive to EGFR-tyrosine kinase inhibitors (TKIs) treatment, but soon develop an acquired resistance. The treatment effect of EGFR-TKIs-resistant NSCLC patients still faces challenges. Cucurbitacin B (CuB), a triterpene hydrocarbon compound isolated from plants of various families and genera, elicits anticancer effects in a variety of cancer types. However, whether CuB is a viable treatment option for gefitinib-resistant (GR) NSCLC remains unclear. Here, we investigated the anticancer effects and underlying mechanisms of CuB. We report that CuB inhibited the growth and invasion of GR NSCLC cells and induced apoptosis. The inhibitory effect of CuB occurred through its promotion of the lysosomal degradation of EGFR and the downregulation of the cancerous inhibitor of protein phosphatase 2A/protein phosphatase 2A/Akt (CIP2A/PP2A/Akt) signaling axis. CuB and cisplatin synergistically inhibited tumor growth. A xenograft tumor model indicated that CuB inhibited tumor growth in vivo. Immunohistochemistry results further demonstrated that CuB decreased EGFR and CIP2A levels in vivo. These findings suggested that CuB could suppress the growth and invasion of GR NSCLC cells by inducing the lysosomal degradation of EGFR and by downregulating the CIP2A/PP2A/Akt signaling axis. Thus, CuB may be a new drug candidate for the treatment of GR NSCLC.

Cucurbitacin B inhibits the migration and invasion of breast cancer cells by altering the biomechanical properties of cells

Changes in cellular biomechanical properties affect cell migration and invasion. The natural compound Cucurbitacin B (CuB) has potent anticancer activity; however, the mechanism underlying its inhibitory effect on breast cancer metastasis needs further study. Here, we showed that low-dose CuB inhibited adhesion and altered the viscoelasticity of breast cancer cells, thereby, reducing cell deformability. In vitro and in vivo experiments proved that CuB effectively inhibited the migration and invasion of breast cancer cells. Further studies have found that CuB downregulated the expression of F-actin/vimentin/FAK/vinculin in breast cancer cells, altering the distribution and reorganization of cytoskeletal proteins in the cells. CuB inhibited signaling by the Rho family GTPases RAC1/CDC42/RhoA downstream of integrin. These findings indicate that CuB has been proven to mediate the reorganization and distribution of cytoskeletal proteins of breast cancer cells through RAC1/CDC42/RhoA signaling, which improves the mechanical properties of cell adhesion and deformation and consequently inhibits cell migration and invasion.

MIR31HG promotes cell proliferation and invasion by activating the Wnt/β-catenin signaling pathway in non-small cell lung cancer

Long non-coding RNAs (lncRNAs) have recently been demonstrated to serve crucial roles in various diseases including tumor initiation and progression. However, the role of the lncRNA MIR31HG in non-small cell lung cancer (NSCLC) was not well established. The present study demonstrated that MIR31HG was significantly increased in tumor tissues compared with adjacent normal tissues, and increased MIR31HG expression levels were associated with histological differentiation grade, lymph node metastasis and Tumor-node metastasis (TNM) stage in patients with NSCLC. Patients who had a higher MIR31HG expression level, were predicted a shorter over survival (OS) time. Using in vitro assays, the present study demonstrated that the downregulation of MIR31HG expression significantly inhibited cell proliferation and cell invasion abilities. Furthermore, it was identified that knockdown of MIR31HG expression suppressed the cell epithelial-mesenchymal transition (EMT) phenotype by reducing the expression levels of Twist1 and Vimentin, but also increased the expression level of E-cadherin in NSCLC cells. Furthermore, the results of the present study demonstrated that downregulated MIR31HG inhibited the Wnt/β-catenin signaling pathway by decreasing the expression of glycogen synthase kinase 3β (GSK3β) and β-catenin, but increasing the phosphorylated (p)-GSK3β expression in NSCLC cells. Together, these data demonstrated that MIR31HG could be identified as a poor prognostic biomarker and a novel therapeutic target for patients with NSCLC.

MicroRNA-122 negatively associates with peroxiredoxin-II expression in human gefitinib-resistant lung cancer stem cells

Previously, we demonstrated that Prx II is important for survival of the gefitinib-resistant A549 (A549/GR) cell line, an NSCLC cell line derived by repeated exposure to gefitinib. Therefore, in this study, we used A549/GR cells to investigate the role of Prx II in GR NSCLC stemness. Initially, to explore the stemness characteristics and investigate the association of Prx II with those stemness characteristics, we successfully isolated a stem cell-like population from A549/GR cells. A549/GR CD133⁺ cells possessed important cancer stemness characteristics, including the abilities to undergo metastasis, angiogenesis, self-renewal, and to express stemness genes and epithelial–mesenchymal transition (EMT) markers. However, those characteristics were abolished by knocking down Prx II expression. MicroRNA 122 (miR-122) targets Prx II in A549/GR cancer stem cells (CSCs), thereby inhibiting the stemness characteristics in vitro and in vivo. Next, we investigate whether miR-122 overexpression was associated with Prx II expression and Prx-II-induced stemness characteristics, we transfected miR-122 into A549/GR CSCs. MiR-122 inhibited A549/GR stemness by downregulating the Hedgehog, Notch, and Wnt/β-catenin pathways. Taken together, our data suggest that Prx II promotes A549/GR stemness, and that targeting Prx II and miR-122 is a potentially viable strategy for anti-cancer-stem cell therapy in GR NSCLCs.

Emerging functional markers for cancer stem cell-based therapies: Understanding signaling networks for targeting metastasis

Metastasis is one of the most challenging issues in cancer patient management, and effective therapies to specifically target disease progression are missing, emphasizing the urgent need for developing novel anti-metastatic therapeutics. Cancer stem cells (CSCs) gained fast attention as a minor population of highly malignant cells within liquid and solid tumors that are responsible for tumor onset, self-renewal, resistance to radio- and chemotherapies, and evasion of immune surveillance accelerating recurrence and metastasis. Recent progress in the identification of their phenotypic and molecular characteristics and interactions with the tumor microenvironment provides great potential for the development of CSC-based targeted therapies and radical improvement in metastasis prevention and cancer patient prognosis. Here, we report on newly uncovered signaling mechanisms controlling CSC's aggressiveness and treatment resistance, and CSC-specific agents and molecular therapeutics, some of which are currently under investigation in clinical trials, gearing towards decisive functional CSC intrinsic or surface markers. One special research focus rests upon subverted regulatory pathways such as insulin-like growth factor 1 receptor signaling and its interactors in metastasis-initiating cell populations directly related to the gain of stem cell- and EMT-associated properties, as well as key components of the E2F transcription factor network regulating metastatic progression, microenvironmental changes, and chemoresistance. In addition, the study provides insight into systems biology tools to establish complex molecular relationships behind the emergence of aggressive phenotypes from high-throughput data that rely on network-based analysis and their use to investigate immune escape mechanisms or predict clinical outcome-relevant CSC receptor signaling signatures. We further propose that customized vector technologies could drastically enhance systemic drug delivery to target sites, and summarize recent progress and remaining challenges. This review integrates available knowledge on CSC biology, computational modeling approaches, molecular targeting strategies, and delivery techniques to envision future clinical therapies designed to conquer metastasis-initiating cells.

Cucurbitacin B inhibits tumor angiogenesis by triggering the mitochondrial signaling pathway in endothelial cells

Cucurbitacin B (CuB), the active component of a traditional Chinese herbal medicine, Pedicellus Melo, has been shown to exhibit antitumor and anti-inflammation effects, but its role in tumor angiogenesis, the key step involved in tumor growth and metastasis, and the involved molecular mechanism are unknown. Tumor angiogenesis is one of the hallmarks of the development in malignant neoplasias and metastasis. Effective targeting of tumor angiogenesis is a key area of interest for cancer therapy. Here, we demonstrated that CuB significantly inhibited human umbilical vascular endothelial cell (HUVEC) proliferation, migration, tubulogenesis in vitro, and blocked angiogenesis in chick embryo chorioallantoic membrane (CAM) assay in vivo. Furthermore, CuB induced HUVEC apoptosis and may induce apoptosis by triggering the mitochondrial apoptotic pathway. Finally, we found that CuB inhibiting angiogenesis was associated with inhibition of the activity of vascular endothelial growth factor receptor 2 (VEGFR2). Our investigations suggested that CuB was a potential drug candidate for angiogenesis related diseases.

Loss of long noncoding RNA FOXF1-AS1 regulates epithelial-mesenchymal transition, stemness and metastasis of non-small cell lung cancer cells

Although recent evidence shows that long noncoding RNAs (lncRNAs) are involved in the regulation of gene expression and cancer progression, the understanding of the role of lncRNAs in lung cancer metastasis is still limited. To identify novel lncRNAs in non-small cell lung cancer (NSCLC), we profile NSCLC tumor and matched normal samples using GeneChip® Human Gene 2.0 ST Array, which provides the most accurate, sensitive, and comprehensive measurement of protein coding and lncRNA transcripts. We identified a panel of key factors dysregulated in lung cancer. Among them, the expression of FOXF1-AS1 was significantly downregulated in lung cancer. Stable overexpression of FOXF1-AS1 inhibits lung cancer cell migration and invasion by regulating EMT. Meanwhile, loss of FOXF1-AS1 mediates stem-like properties of lung cancer cells. Interestingly, we found that FOXF1-AS1 physically associates with PRC2 components EZH2 and loss of FOXF1-AS1 mediates cell migration and stem-like properties require EZH2. Loss of FOXF1-AS1 is also correlated with downregulation of FOXF1 in lung cancer. These results suggested that FOXF1-AS1 might regulate EMT, stemness and metastasis of NSCLC cells via EZH2, indicating it as a therapeutic target for future treatment of NSCLC.

Cucurbitacin B and cancer intervention: Chemistry, biology and mechanisms (Review)

Cancer is one of the most important healthcare matters, with the worst prognosis but the best possibilities for scientific development. It is likely to increase in the future and cause global havoc designating it as an epidemic. Cancer development requires urgent intervention. Past few decades have witnessed extensive research to challenge carcinogenesis. Treatment involving synthetic discipline is often associated with severe adverse effects, or even worsened prognosis. Accordingly, newer economic and patient friendly molecules are warranted. Many natural substances have proved their potential so far. Cucurbitacin B against cancer and other diseases has achieved towering popularity among the researchers around the world, as detailed in the below sections with summarized tables. In line with the fascinating role of cucurbitacin B against various types of cancers, through various molecular signaling pathways, it is justifiable to propose cucurbitacin B as a mainline chemotherapy before the onset and after the diagnosis of cancer.

LncRNA FEZF1-AS1 enhances epithelial-mesenchymal transition (EMT) through suppressing E-cadherin and regulating WNT pathway in non-small cell lung cancer (NSCLC)

OBJECTIVE

Recent discoveries verify that long non-coding RNAs (lncRNAs) are important functional regulators involved in non-small cell lung cancer (NSCLC) progression. However, long non-coding RNA FEZF1-AS1 was not been investigated in NSCLC so for.

METHODS

We applied the quantitative real time polymerase chain reaction (qRT-PCR) assays to detect the expression of lncRNA FEZF1-AS1 in NSCLC tissues and adjacent normal tissues. Cell proliferation and invasion capacities were evaluated by MTT, colony formation, and cell invasion assays. Chromatin immunoprecipitation (ChIP) and RNA immunoprecipitation (RIP) methods demonstrated the association between lncRNA FEZF1-AS1 expression and E-cadherin. The relative protein expression levels were analyzed by western blot analysis.

RESULTS

LncRNA FEZF1-AS1 was significantly up-regulated in NSCLC tissues compared with adjacent normal tissues. Higher lncRNA FEZF1-AS1 expression levels associated with lymph node metastasis, poor differentiation grade and advanced TNM stage. In vitro, we revealed that down-regulation of lncRNA FEZF1-AS1 inhibited cell proliferation and cell invasion capacities in NSCLC. Moreover, down-regulation of lncRNA FEZF1-AS1 suppressed cell epithelial-mesenchymal transition (EMT) process by increasing the expression of E-cadherin and ZO-1, whereas, decreasing the expression of Slug, Twist and Vimentin in NSCLC cells. Furthermore, we demonstrated lncRNA FEZF1-AS1 could epigenetically repress the expression of E-cadherin via binding with LSD1 and EZH2 in NSCLC cells. We also revealed that knockdown of lncRNA FEZF1-AS1 suppressed Wnt/β-catenin signaling in NSCLC.

CONCLUSION

These results demonstrated that lncRNA FEZF1-AS1 could function as a tumor promoting regulator in NSCLC, which may provide a target of treatment in NSCLC.

WNT signaling - lung cancer is no exception

Since the initial discovery of the oncogenic activity of WNT ligands our understanding of the complex roles for WNT signaling pathways in lung cancers has increased substantially. In the current review, the various effects of activation and inhibition of the WNT signaling pathways are summarized in the context of lung carcinogenesis. Recent evidence regarding WNT ligand transport mechanisms, the role of WNT signaling in lung cancer angiogenesis and drug transporter regulation and the importance of microRNA and posttranscriptional regulation of WNT signaling are also reviewed.