Wnt signaling regulation of stem-like properties in human lung adenocarcinoma cell lines

Targeting NF-κB signaling cascades of glioblastoma by a natural benzophenone, garcinol, via in vitro and molecular docking approaches

Glioblastoma multiforme (GBM) is regarded as the most aggressive form of brain tumor delineated by high cellular heterogeneity; it is resistant to conventional therapeutic regimens. In this study, the anti-cancer potential of garcinol, a naturally derived benzophenone, was assessed against GBM. During the analysis, we observed a reduction in the viability of rat glioblastoma C6 cells at a concentration of 30 µM of the extract (p < 0.001). Exposure to garcinol also induced nuclear fragmentation and condensation, as evidenced by DAPI-stained photomicrographs of C6 cells. The dissipation of mitochondrial membrane potential in a dose-dependent fashion was linked to the activation of caspases. Furthermore, it was observed that garcinol mediated the inhibition of NF-κB (p < 0.001) and decreased the expression of genes associated with cell survival (Bcl-XL, Bcl-2, and survivin) and proliferation (cyclin D1). Moreover, garcinol showed interaction with NF-κB through some important amino acid residues, such as Pro275, Trp258, Glu225, and Gly259 during molecular docking analysis. Comparative analysis with positive control (temozolomide) was also performed. We found that garcinol induced apoptotic cell death via inhibiting NF-κB activity in C6 cells, thus implicating it as a plausible therapeutic agent for GBM.

Propofol inhibits colon cancer cell stemness and epithelial-mesenchymal transition by regulating SIRT1, Wnt/β-catenin and PI3K/AKT/mTOR signaling pathways

BACKGROUND

Propofol is a common sedative-hypnotic drug used for general anesthesia. Recent studies have drawn attention to the antitumor effects of propofol, but the potential mechanism by which propofol suppresses colon cancer stemness and epithelial-mesenchymal transition (EMT) has not been fully elucidated.

METHODS

For the in vitro experiments, we used propofol to treat LOVO and SW480 cells and Cell Counting Kit-8 (CCK-8) to detect proliferation. Self-renewal capacity, cell invasion and migration, flow cytometry analysis, qPCR and Western blotting were performed to detect the suppression of propofol to colon cancer cells and the underlying mechanism. Tumorigenicity and immunohistochemistry experiments were performed to confirm the role of propofol in vivo.

RESULT

We observed that propofol could suppressed stem cell-like characteristics and EMT-related behaviors, including self-renewal capacity, cell invasion and migration in colon cancer cells, and even suppressed tumorigenicity in vivo. Furthermore, investigations of the underlying mechanism revealed that propofol treatment downregulated SIRT1. SIRT1 overexpression or knockdown affected the stemness and EMT of colon cancer cells. Additionally, propofol reversed stemness and EMT in cells with overexpressing SIRT1 and subsequently inhibited the Wnt/β-catenin and PI3K/AKT/mTOR signaling pathways. Wnt/β-catenin pathway inhibitor and PI3K/AKT/mTOR pathway inhibitor blocked the propofol-induced reduction of sphere-formation and cell invasion-migration.

CONCLUSION

Propofol inhibits LOVO and SW480 cell stemness and EMT by regulating SIRT1 and the Wnt/β-catenin and PI3K/AKT/mTOR signaling pathways. Our findings indicate that propofol inhibits SIRT1 in cancer and is advantageous in colon cancer surgical treatment of patients with high SIRT1 expression.

Ethanolic Extract of Artemisia vulgaris Leaf Promotes Apoptotic Cell Death in Non-Small-Cell Lung Carcinoma A549 Cells through Inhibition of the Wnt Signaling Pathway

The Wnt signaling pathway is reported to be associated with lung cancer progression, metastasis and drug resistance, and thus it is an important therapeutic target for lung cancer. Plants have been shown as reservoirs of multiple potential anticancer agents. In the present investigation, the ethanolic leaf extract of Artemisia vulgaris (AvL-EtOH) was initially analyzed by means of gas chromatography-mass spectrometry (GC–MS) to identify the important phytochemical constituents. The GC–MS analysis of AvL-EtOH exhibited 48 peaks of various secondary metabolites such as terpenoids, flavonoids, carbohydrates, coumarins, amino acids, steroids, proteins, phytosterols, and diterpenes. It was found that the treatment with increasing doses of AvL-EtOH suppressed the proliferation and migration of lung cancer cells. Furthermore, AvL-EtOH induced prominent nuclear alteration along with a reduction in mitochondrial membrane potential and increased ROS (reactive oxygen species) generation in lung cancer cells. Moreover, AvL-EtOH-treated cells exhibited increased apoptosis, demonstrated by the activation of caspase cascade. AvL-EtOH also induced downregulation of Wnt3 and β-catenin expression along with cell cycle protein cyclin D1. Thus, the results of our study elucidated the potential of bioactive components of Artemisia vulgaris in the therapeutic management of lung cancer cells.

Undescribed isoquinolines from Zanthoxylum nitidum and their antiproliferative effects against human cancer cell lines

Eleven previously undescribed alkaloids, including three pairs of enantiomers nitidumalkaloids A-C, a pair of scalemic mixtures nitidumalkaloid D and three optically pure or achiral alkaloids, nitidumalkaloids E-G, along with 20 known alkaloids, were isolated from an ethanolic extract of the whole Zanthoxylum nitidum (Roxb.) DC plant. The chemical structures of the alkaloids were elucidated using a combination of comprehensive nuclear magnetic resonance (NMR) and high-resolution electro-spray ionization mass spectrometry (HR-ESI-MS) analyses. The configuration of the stereogenic centers of all undescribed compounds was precisely established based on single-crystal X-ray diffraction and electronic circular dichroism (ECD) calculations. Racemic mixtures of nitidumalkaloids A-D were purified, and their enantiomers were analyzed via chiral-phase high-performance liquid chromatography with electrochemical detection measurements (HPLC-ECD). Twelve compounds exhibited significant antiproliferative activities against a panel of cancer cell lines. Further studies were designed to investigate the underlying molecular mechanism of (1'S, 6R)-nitidumalkaloid B, which was the most active antiproliferative agent against human cancer A549 cells. G2/M cell cycle arrest, induction of apoptosis, and suppression of the Wnt/β-catenin signaling pathway were in part associated with the antiproliferative activity of (1'S, 6R)-nitidumalkaloid B. Moreover, (1'S, 6R)-nitidumalkaloid B inhibited cell migration by downregulating the epithelial-mesenchymal transition process in A549 cells. These data suggest that the antiproliferation activity of (1'S, 6R)-nitidumalkaloid B was correlated with the stereoselectivity of the stereoisomers, and (1'S, 6R)-nitidumalkaloid B was prioritized as a potential leading compound for the management of aggressive human non-small-cell lung cancer (NSCLC) from natural products.

Screening of Apoptosis Pathway-Mediated Anti-Proliferative Activity of the Phytochemical Compound Furanodienone against Human Non-Small Lung Cancer A-549 Cells

Furanodienone (FDN), a major bioactive component of sesquiterpenes produced from Rhizoma Curcumae, has been repeatedly acknowledged for its intrinsic anticancer efficacy against different types of cancer. In this study, we aimed to investigate the cytotoxic potential of furanodienone against human lung cancer (NSCLC A549) cells in vitro, as well as its underlying molecular mechanisms in the induction of apoptosis. Herein, we found that FDN significantly inhibited the proliferation of A549 cells in a dose-dependent manner. In addition, treatment with FDN potentially triggered apoptosis in A549 cells via not only disrupting the nuclear morphology, but by activating capsase-9 and caspase-3 with concomitant modulation of the pro- and antiapoptotic gene expression as well. Furthermore, FDN revealed its competence in inducing cell cycle arrest at G0/G1 phase in A549 cells, which was associated with decreased expression of cyclin D1 and cyclin-dependent kinase 4 (CDK4), along with increased expression of CDK inhibitor p21Cip1. Intriguingly, FDN treatment efficiently downregulated the Wnt signaling pathway, which was correlated with increased apoptosis, as well as cell cycle arrest, in A549 cells. Collectively, FDN might represent a promising adjuvant therapy for the management of lung cancer.

Impact of Cancer Stem Cells and Cancer Stem Cell-Driven Drug Resiliency in Lung Tumor: Options in Sight

Causing a high mortality rate worldwide, lung cancer remains an incurable malignancy resistant to conventional therapy. Despite the discovery of specific molecular targets and new treatment strategies, there remains a pressing need to develop more efficient therapy to further improve the management of this disease. Cancer stem cells (CSCs) are considered the root of sustained tumor growth. This consensus corroborates the CSC model asserting that a distinct subpopulation of malignant cells within a tumor drives and maintains tumor progression with high heterogeneity. Besides being highly tumorigenic, CSCs are highly refractory to standard drugs; therefore, cancer treatment should be focused on eliminating these cells. Herein, we present the current knowledge of the existence of CSCs, CSC-associated mechanisms of chemoresistance, the ability of CSCs to evade immune surveillance, and potential CSC inhibitors in lung cancer, to provide a wider insight to drive a more efficient elimination of this pro-oncogenic and treatment-resistant cell fraction.

Silencing LGR6 Attenuates Stemness and Chemoresistance via Inhibiting Wnt/β-Catenin Signaling in Ovarian Cancer

Leucine-rich-repeat-containing G protein-coupled receptors (LGRs) have been widely found to be implicated with development and progression in multiple cancer types. However, the clinical significance and biological functions of LGR6 in ovarian cancer remains unclear. In this study, LGR6 expression was mainly examined by immunohistochemistry. Functional assays in vitro and animal experiments in vivo were carried out to explore the effect of LGR6 on cancer stem cell (CSC) characteristics and chemotherapeutic responses in ovarian cancer cells. Luciferase assays and GSEA were used to discern the underlying mechanisms contributing to the roles of LGR6 in ovarian cancer. Here, we reported that LGR6 was upregulated in ovarian cancer, which positively correlated with poor chemotherapeutic response and progression survival in ovarian cancer patients. Loss-of-function assays showed that downregulating LGR6 abrogated the CSC-like phenotype and chemoresistance in vitro. More importantly, silencing LGR6 improved the chemoresistance of ovarian cancer cells to cisplatin in vivo. Mechanistic investigation further revealed that silencing LGR6 inhibited stemness and chemoresistance by repressing Wnt/β-catenin signaling. Collectively, our results uncover a novel mechanism contributing to LGR6-induced chemotherapeutic resistance in ovarian cancer, providing the evidence for LGR6 as a potential therapeutic target in ovarian cancer.

miR-26a prevents neural stem cells from apoptosis via β-catenin signaling pathway in cardiac arrest-induced brain damage

Neural stem cells (NSCs) transplantation is one of the most promising strategies for the treatment of CA-induced brain damage. The transplanted NSCs could differentiate into new neuron and replace the damaged one. However, the poor survival of NSCs in severe hypoxic condition is the limiting step to make the best use of this kind of therapy. In the present study, we investigated whether the overexpression of miR-26a improves the survival of NSCs in hypoxic environment in vitro and in vivo. In vitro hypoxia injury model is established in NSCs by CoCl₂ treatment, and in vivo cardiac arrest (CA) model is established in Sprague-Dawley (SD) rats. Quantitative real-time polymerase chain reaction is used to detect the mRNA level and Western blot is used to examine the protein level of indicated genes. TUNEL staining and flow cytometry are applied to evaluate apoptosis. Dual-luciferase reporter assay is utilized to analyze the target gene of miR-26a. The expression of miR-26a is reduced in both in vitro and in vivo hypoxic model. MiR-26a directly targets 3′-UTR of glycogen synthase kinase 3β (GSK-3β), resulting in increased β-catenin expression and decreased apoptosis of NSCs. Overexpression of miR-26a in transplanted NSCs improves the survival of NSCs and neurological function in CA rats. MiR-26a prevents NSCs from apoptosis by activating β-catenin signaling pathway in CA-induced brain damage model. Modulating miR-26a expression could be a potential strategy to attenuate brain damage induced by CA.

Synergistic effect of targeting dishevelled-3 and the epidermal growth factor receptor-tyrosine kinase inhibitor on mesothelioma cells in vitro

It was previously revealed that Wnt signaling is activated in mesothelioma cells. Although epidermal growth factor receptor (EGFR) is expressed in mesothelioma cells, EGFR-tyrosine kinase inhibitors (TKIs) are not effective for mesothelioma treatment. However, in non-small cell lung cancer, the blocking of Wnt signaling has been identified to enhance the anticancer effect of EGFR-TKIs. To confirm the anticancer effect of blocking Wnt signaling in combination with EGFR-TKI treatment in mesothelioma, the present study evaluated the effect of simultaneous suppression of human dishevelled-3 (Dvl-3) expression with Dvl-3 small interfering RNA (siRNA) and of EGFR inhibition with gefitinib on mesothelioma cell viability. Mesothelioma cell lines with and without β-catenin gene expression were transfected with Dvl-3 siRNA and were cultured with gefitinib, and cell viability, colony formation and cell cycle analyses were performed. Dvl-3 siRNA downregulated the expression of Dvl-3 in mesothelioma cells. The combination of Dvl-3 siRNA with gefitinib acted synergistically to induce concomitant suppression of cell viability and colony formation, suggesting that inhibition of Wnt signaling by downregulating Dvl-3 with siRNA and inhibiting EGFR with gefitinib leads to significant antitumor effects.

Fentanyl Promotes Breast Cancer Cell Stemness and Epithelial-Mesenchymal Transition by Upregulating α1, 6-Fucosylation via Wnt/β-Catenin Signaling Pathway

Cancer pain is a common and severe complication of human breast cancer, and relieving pain is fundamental strategy in the treatment. Fentanyl, as an opioid analgesic, is widely used in breast cancer patients. However, little is known about its effects on stemness and epithelial-mesenchymal transition (EMT) of breast cancer cells. Aberrant protein glycosylation is involved in cancer malignancy. The α1, 6-fucosylation is an important type of glycosylation, and the elevated α1, 6-fucosylation catalyzed by fucosyltransferase VIII (FUT8) is found in many tumors. However, whether 1, 6-fucosylation is involved in regulating stemness and EMT, and stimulated by fentanyl is not clear. In this study, we found that fentanyl induced stemness and EMT in MCF-7 and MDA-MB-231 breast cancer cells by analysis of sphere formation, expression of stemness markers (Sox2, Oct4) and EMT markers (N-cadherin, E-cadherin and Vimentin). Results also showed that fentanyl upregulated FUT8 gene and protein expression by qPCR, Western blot and immunofluorescent staining, as well as α1, 6-fucosylation level by Lectin blot and Lectin fluorescent staining. Furthermore, decreased or blocked α1, 6-fucosylation by FUT8 siRNA transfection or LCA Lectin blockage reduced stemness and EMT. Additionally, fentanyl activated the key molecules and target genes in Wnt/β-catenin signaling pathway. LGK-974 (an inhibitor of Wnt ligands) suppressed fentanyl-mediated upregulation of α1, 6-fucosylation, stemness and EMT. The results of tumor xenograft demonstrated that fentanyl enhanced tumor growth, α1, 6-fucosylation, stemness and EMT. Taken together, our study reveals that fentanyl upregulated FUT8 expression, which increased α1, 6-fucosylation level through activation of Wnt/β-catenin signaling pathway, thereby, induce stemness and EMT of breast cancer cells. This study suggest a potential side effect of fentanyl in the treatment of cancer, which may guide the safety of fentanyl in the clinical application.

DISC1 overexpression promotes non-small cell lung cancer cell proliferation

Neuropsychiatric disorder-associated disrupted-in-schizophrenia-1 (DISC1) activates Wnt/β-catenin signaling by inhibiting glycogen synthase kinase 3 beta (GSK3β) phosphorylation, and may promote neural progenitor cell and pancreatic β-cell proliferation. The present study found that DISC1 promotes non-small cell lung cancer (NSCLC) cell growth. Western blotting and immunohistochemistry analyses showed that DISC1 was highly expressed in NSCLC cell lines and patient tissues. DISC1 expression was negatively associated with phosphorylated (p-) GSK3β, but positively correlated with a more invasive tumor phenotype and predicted poor NSCLC patient prognosis. siRNA-mediated DISC1 silencing increased p-GSK3β expression and decreased expression of β-catenin and Cyclin D1, while DISC1 upregulation produced the opposite results. DISC1 knockdown also reduced NSCLC cell proliferation rates in vitro. These results suggest that DISC1 promotes NSCLC growth, likely through GSK3β/β-catenin signaling, and that DISC1 may function as an oncogene and novel anti-NSCLC therapeutic target.

Anti-Cancer Phytometabolites Targeting Cancer Stem Cells

Medicinal plants are a plentiful source of bioactive molecules with much structural diversity. In cancer treatment, molecules obtained from plants represent an attractive alternative to other treatments because several plant-derived compounds have exhibited lower toxicity and higher selectivity against cancer cells. In this review, we focus on the possible application of bioactive molecules obtained from plants against more primitive cell populations in cancers, cancer stem cells. Cancer stem cells are present in several kinds of tumors and are responsible for recurrences and metastases. Common anti-cancer drugs exhibit lower effectiveness against cancer stem cells because of their biological features. However, recently discovered natural phytometabolites exert cytotoxic effects on this rare population of cells in cancers. Therefore, this review presents the latest research on promising compounds from plants that can act as antitumor drugs and that mainly affect stem cell populations in cancers.

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

Lack of effective anti-metastatic drugs creates a major hurdle for metastatic lung cancer therapy. For successful lung cancer treatment, there is a strong need of newer therapeutics with metastasis-inhibitory potential. In the present study, we determined the anti-metastatic and anti-angiogenic potential of a natural plant triterpenoid, Cucurbitacin B (CuB) against non-small cell lung cancer (NSCLC) both in vitro and in vivo. CuB demonstrated a strong anti-migratory and anti-invasive ability against metastatic NSCLC at nanomolar concentrations. CuB also showed significant tumor angiogenesis-inhibitory effects as evidenced by the inhibition of migratory, invasive and tube-forming capacities of human umbilical vein endothelial cells. CuB-mediated inhibition of angiogenesis was validated by the inhibition of pre-existing vasculature in chick embryo chorio-allantoic membrane and matrigel plugs. Similarly, CuB inhibited the migratory behavior of TGF-β1-induced experimental EMT model. The CuB-mediated inhibition of metastasis and angiogenesis was attributable to the downregulation of Wnt/β-catenin signaling axis, validated by siRNA-knockdown of Wnt3 and Wnt3a. The CuB-mediated downregulation of Wnt/β-catenin signaling was also validated using 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis model in vivo. Collectively, our findings suggest that CuB inhibited the metastatic abilities of NSCLC through the inhibition of Wnt/β-catenin signaling axis.

Lethality of opioid and antihistaminic combinations in mice

Ell3 is an RNA polymerase II transcription elongation factor that acts as a negative regulator of p53 expression, and regulates cell proliferation and survival. Recent studies by our group have demonstrated that ectopic expression of Ell3 in breast cancer cell lines enhances cell proliferation, potentiates cancer stem cell properties, and promotes 5-Fluorouracil (5-FU) resistance. In the present study, the underlying mechanism for the induction of 5-FU resistance was investigated in Ell3 over-expressing MCF-7 cells (Ell3 OE cells). By comparing the gene expression profiles of Ell3 OE cells with control cells, the present data revealed that Lipocalin2 (LCN2) and Wnt signaling activity are associated with 5-FU resistance of Ell3 OE. siRNA-mediated suppression of LCN2 reversed 5-FU resistance in Ell3 OE cells. Chemical inhibition of Wnt signaling also reversed 5-FU resistance in Ell3 OE cells. Furthermore, the expression levels of survivin, which is a direct transcriptional target of Wnt/β-catenin and an inhibitor of apoptosis, were markedly elevated when Ell3 OE cells were treated with 5-FU, as detected by western blot analysis. These findings suggest that enhanced expression of LCN2 and activation of the Wnt signaling pathway may induce 5-FU resistance in Ell3 OE cells as a means of evading apoptosis.