Induction of Egr-1 is associated with anti-metastatic and anti-invasive ability of beta-lapachone in human hepatocarcinoma cells

Adefovir Dipivoxil as a Therapeutic Candidate for Medullary Thyroid Carcinoma: Targeting RET and STAT3 Proto-Oncogenes

Aberrant gene expression is often linked to the progression of various cancers, making the targeting of oncogene transcriptional activation a potential strategy to control tumor growth and development. The RET proto-oncogene’s gain-of-function mutation is a major cause of medullary thyroid carcinoma (MTC), which is part of multiple endocrine neoplasia type 2 (MEN2) syndrome. In this study, we used a cell-based bioluminescence reporter system driven by the RET promoter to screen for small molecules that potentially suppress the RET gene transcription. We identified adefovir dipivoxil as a transcriptional inhibitor of the RET gene, which suppressed endogenous RET protein expression in MTC TT cells. Adefovir dipivoxil also interfered with STAT3 phosphorylation and showed high affinity to bind to STAT3. Additionally, it inhibited RET-dependent TT cell proliferation and increased apoptosis. These results demonstrate the potential of cell-based screening assays in identifying transcriptional inhibitors for other oncogenes.

EGR1 induces EMT in pancreatic cancer via a P300/SNAI2 pathway

BACKGROUND

The prognosis of pancreatic cancer patients remains relatively poor. Although some patients would receive surgical resection, distant metastasis frequently occurs within one year. Epithelial-mesenchymal transition (EMT), as a pathological mechanism in cancer progression, contributed to the local and distant metastasis of pancreatic cancer.

METHODS

Tissue microarray analysis and immunohistochemistry assays were used to compare the expression of EGR1 in pancreatic cancer and normal pancreatic tissues. Transwell chambers were used to evaluated the migration and invasion ability of cancer cells. Immunofluorescence was utilized to assess the expression of E-cadherin. ChIP-qPCR assay was applied to verify the combination of EGR1 and SNAI2 promoter sequences. Dual-luciferase reporter assay was used to detect the gene promoter activation. Co-IP assay was conducted to verify the interaction of EGR1 and p300/CBP.

RESULTS

EGR1 was highly expressed in pancreatic cancer rather than normal pancreatic tissues and correlated with poor prognosis and cancer metastasis. EGR1 was proved to enhance the migration and invasion ability of pancreatic cells. Besides, EGR1 was positively correlated with EMT process in pancreatic cancer, via a SNAI2-dependent pathway. P300/CBP was found to play an auxiliary role in the transcriptional activation of the SNAI2 gene by EGR1. Finally, in vivo experiments also proved that EGR1 promoted liver metastasis of pancreatic cancer.

CONCLUSION

Our findings implied the EMT-promoting effect of EGR1 in pancreatic cancer and revealed the intrinsic mechanism. Blocking the expression of EGR1 may be a new anticancer strategy for pancreatic cancer.

Putative Anticancer Compounds from Plant-Derived Endophytic Fungi: A Review

Endophytic fungi are microorganisms that exist almost ubiquitously inside the various tissues of living plants where they act as an important reservoir of diverse bioactive compounds. Recently, endophytic fungi have drawn tremendous attention from researchers; their isolation, culture, purification, and characterization have revealed the presence of around 200 important and diverse compounds including anticancer agents, antibiotics, antifungals, antivirals, immunosuppressants, and antimycotics. Many of these anticancer compounds, such as paclitaxel, camptothecin, vinblastine, vincristine, podophyllotoxin, and their derivatives, are currently being used clinically for the treatment of various cancers (e.g., ovarian, breast, prostate, lung cancers, and leukemias). By increasing the yield of specific compounds with genetic engineering and other biotechnologies, endophytic fungi could be a promising, prolific source of anticancer drugs. In the future, compounds derived from endophytic fungi could increase treatment availability and cost effectiveness. This comprehensive review includes the putative anticancer compounds from plant-derived endophytic fungi discovered from 1990 to 2020 with their source endophytic fungi and host plants as well as their antitumor activity against various cell lines.

Egr‑1 inhibits colon cancer cell proliferation, migration and invasion via regulating CDKL1 at the transcriptional level

Colon cancer is one of the most common malignant tumors worldwide, and the molecular mechanisms involved in the oncogenesis and progression of colon cancer remain unclear. Early growth response 1 (Egr‑1) is a transcription factor that is closely associated with several tumor processes; however, its role in colon cancer is unknown. The present study aimed to explore the function and mechanism of transcription factor Egr‑1 in colon cancer progression. The association between Egr‑1 expression and the survival of patients with colon cancer was analyzed. Transwell assay was used to measure the migration and invasion of colon cancer cells. Cell Counting Kit‑8 assay was used to evaluate the cell proliferative ability. Reverse transcription‑quantitative PCR and western blot assays were used to identify whether Egr‑1 could regulate cyclin‑dependent kinase‑like 1 (CDKL1). Luciferase and chromatin immunoprecipitation assays were used to detect the mechanism by which Egr‑1 regulated CDKL1. Based on The Cancer Genome Atlas database, it was found that low Egr‑1 expression was associated with a poor prognosis in patients with colon cancer. Furthermore, overexpression of Egr‑1 inhibited colon cancer cell proliferation, migration, and invasion, whereas knockdown of Egr‑1 increased colon cancer cell proliferation, migration and invasion. Additionally, overexpression of Egr‑1‑induced cell proliferation, migration and invasion were reversed by overexpression of CDKL1. Furthermore, it was demonstrated that Egr‑1 regulated CDKL1 expression at the transcriptional level. The present study illustrated the mechanism of Egr‑1 regulating CDKL1, by which Egr‑1 affected colon cancer cell proliferation, migration and invasion. The current findings suggested that Egr‑1/CDKL1 may be a new promising target for the treatment of colon cancer.

The Role of the Transcription Factor EGR1 in Cancer

Early growth response factor 1 (EGR1) is a transcription factor that is mainly involved in the processes of tissue injury, immune responses, and fibrosis. Recent studies have shown that EGR1 is closely related to the initiation and progression of cancer and may participate in tumor cell proliferation, invasion, and metastasis and in tumor angiogenesis. Nonetheless, the specific mechanism whereby EGR1 modulates these processes remains to be elucidated. This review article summarizes possible mechanisms of action of EGR1 in tumorigenesis and tumor progression and may serve as a reference for clinical efficacy predictions and for the discovery of new therapeutic targets.

MicroRNA-34a suppresses the invasion and migration of colorectal cancer cells by enhancing EGR1 and inhibiting vimentin

MicroRNAs (miRNAs/miRs) are small non-coding RNAs that serve a post-transcriptional regulatory role in eukaryotes. Previous studies have demonstrated that the expression of miR-34a in colorectal cancer (CRC) tissues is decreased compared with that in normal colorectal tissues. However, the role of miR-34a in the invasion and metastasis of CRC remains unclear. In the present study, the levels of miR-34a expression were measured in various CRC cell lines. The cells were transfected with miR-34a mimics or inhibitors in order to assess the proliferation rate, and the colony forming, invasive and migratory abilities. Furthermore, the protein expression levels of vimentin and early growth response protein 1 (EGR1) were examined by western blot analysis. The results revealed that the expression of miR-34a was low in SW620, RKO, LoVo and Caco-2 cell lines and high in the SW480 and SW1116 cell lines. The migration, invasion and proliferation levels of SW480 cells were facilitated by decreasing the expression of miR-34a. Transient transfection with miR-34a mimics in SW620 cells caused a notable decrease in cell migration, invasion and proliferation levels compared with the control group, and a downregulation of vimentin and upregulation of EGR1 protein expression. The present study demonstrated that miR-34a was deregulated in a highly invasive CRC cell lines, and that it may attenuate the migratory, invasive and proliferative capabilities of CRC cells by enhancing the expression of EGR1 and inhibiting that of vimentin. The results of the present study represent important progress towards understanding the mechanisms of CRC recurrence and metastasis.

GCN5 inhibition prevents IL-6-induced prostate cancer metastases through PI3K/PTEN/Akt signaling by inactivating Egr-1

General control non-derepressible 5 (GCN5) is ectopically expressed in different types of human cancer and association with the carcinogenesis, development, and poor prognosis of cancers. The present study was aimed to investigate the potential role and related mechanisms of GCN5 in IL-6–treated prostate cancer (PCa) cell. The results showed that an elevated GCN5 expression was stimulated by IL-6. Knockdown of GCN5 significantly inhibited IL-6–driven proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT). Moreover, early growth response-1 (Egr-1) expression was elevated by IL-6 treatment and GCN5 siRNA down-regulated the expression of Egr-1. Furthermore, overexpression of Egr-1 attenuated the effects of GCN5 silence on cell proliferation, migration, invasion, and EMT in PCa. Besides, knockdown of GCN5 resulted in the down-regulation of p-Akt and up-regulation of PTEN, which was partly impeded by Egr-1 overexpression. The effects of GCN5 overexpression on cell proliferation and invasion were suppressed by LY294002, In conclusion, these data demonstrated the negative effect of up-regulated GCN5 in IL-6-induced metastasis and EMT in PCa cells through PI3K/PTEN/Akt signaling pathway down-regulating Egr-1 expression.

Daphnane diterpenes inhibit the metastatic potential of B16F10 murine melanoma cells in vitro and in vivo

BACKGROUND

Melanoma is one of the most invasive and aggressive types of cancer with a very poor prognosis. Surgery remains the most efficient treatment prior melanoma invasion and metastasis formation. However, therapy becomes a challenge once the cancer cells colonized other tissues. At present, there are two main classes of therapies acting with a certain efficiency on metastatic melanoma: immune check point inhibitors (anti-PD1/PDL1) and targeted therapy such as Vemurafenib. Unfortunately, these therapies are not fully responsive, induce resistance and/or generate unwanted side effects. In this respect, it is important to continue to discover new cancer therapeutics. Here, we show that daphnane diterpenes type of compounds can prevent melanoma metastasis by inhibiting metastasis-associated matrix metalloproteinases expression without cytotoxicity.

METHODS

Evaluation of the anti-metastasis effect of daphnane diterpenes-rich Thymelaea hirsuta extract (TH) and its bioactive component gnidilatidin was carried out in vitro using B16 murine melanoma cells and in vivo using male C57BL/6 J mice. Global gene expression in B16 cells was done using DNA microarray, validated using real-time PCR, to further understand the effect of daphnane diterpenes, specifically daphnane diterpenoid gnidilatidin.

RESULTS

Oral administration of daphnane diterpenes-rich Thymelaea hirsuta extract (TH) suppressed MMP2 and MMP9 expression, decreasing lung tumor in mice injected with B16 murine melanoma cells. Validation of these observations in vitro showed reduced B16 cells migration, adhesion, and invasion. Results of microarray analysis of B16 cells treated with daphnane diterpenoid gnidilatidin from TH revealed an upregulation of tumor suppressor Egr1 while inhibiting metastasis-associated genes Id2 and Sytl2 expression. A downregulation of the melanoma oncogene microphthalmia-associated transcription factor (Mitf) was observed, and most likely caused by the inhibition of Id2, a gene that regulated HLH transcription factors such as MITF and also reported to promote tumor cell migration and invasion.

CONCLUSIONS

Daphnane diterpenes have inhibitory effect on the metastatic potential of B16 melanoma cells, and the results of this study provided evidence for their potential for use in the prevention and inhibition of melanoma metastasis.

Identification of Biological Targets of Therapeutic Intervention for Hepatocellular Carcinoma by Integrated Bioinformatical Analysis

BACKGROUND We screened the potential molecular targets and investigated the molecular mechanisms of hepatocellular carcinoma (HCC). MATERIAL AND METHODS Microarray data of GSE47786, including the 40 μM berberine-treated HepG2 human hepatoma cell line and 0.08% DMSO-treated as control cells samples, was downloaded from the GEO database. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses were performed; the protein-protein interaction (PPI) networks were constructed using STRING database and Cytoscape; the genetic alteration, neighboring genes networks, and survival analysis of hub genes were explored by cBio portal; and the expression of mRNA level of hub genes was obtained from the Oncomine databases. RESULTS A total of 56 upregulated and 8 downregulated DEGs were identified. The GO analysis results were significantly enriched in cell-cycle arrest, regulation of transcription, DNA-dependent, protein amino acid phosphorylation, cell cycle, and apoptosis. The KEGG pathway analysis showed that DEGs were enriched in MAPK signaling pathway, ErbB signaling pathway, and p53 signaling pathway. JUN, EGR1, MYC, and CDKN1A were identified as hub genes in PPI networks. The genetic alteration of hub genes was mainly concentrated in amplification. TP53, NDRG1, and MAPK15 were found in neighboring genes networks. Altered genes had worse overall survival and disease-free survival than unaltered genes. The expressions of EGR1, MYC, and CDKN1A were significantly increased, but expression of JUN was not, in the Roessler Liver datasets. CONCLUSIONS We found that JUN, EGR1, MYC, and CDKN1A might be used as diagnostic and therapeutic molecular biomarkers and broaden our understanding of the molecular mechanisms of HCC.

Tabetri™ (Tabebuia avellanedae Ethanol Extract) Ameliorates Atopic Dermatitis Symptoms in Mice

Tabebuia avellanedae has been traditionally used as an herbal remedy to alleviate various diseases. However, the plant's pharmacological activity in allergic and inflammatory diseases and its underlying mechanism are not fully understood. Therefore, we investigated the pharmacological activity of Tabetri (T. avellanedae ethanol extract (Ta-EE)) in the pathogenesis of AD. Its underlying mechanism was explored using an AD mouse model and splenocytes isolated from this model. Ta-EE ameliorated the AD symptoms without any toxicity and protected the skin of 2,4-dinitrochlorobenzene- (DNCB-) induced AD mice from damage and epidermal thickness. Ta-EE reduced the secreted levels of allergic and proinflammatory cytokines, including histamine, immunoglobulin E (IgE), interleukin- (IL-) 4, and interferon-gamma (IFN-γ) in the DNCB-induced AD mice. Ta-EE suppressed the mRNA expression of T helper 2-specific cytokines, IL-4 and IL-5, and the proinflammatory cytokine IFN-γ in the atopic dermatitis skin lesions of AD mice. Moreover, Ta-EE suppressed the mRNA expression of IL-4, IL-5, IFN-γ, and another proinflammatory cytokine, IL-12, in the Con A-stimulated splenocytes. It also suppressed IL-12 and IFN-γ in the LPS-stimulated splenocytes. Taken together, these results suggest that Ta-EE protects against the development of AD through the inhibition of mRNA expression of T helper 2-specific cytokines and other proinflammatory cytokines.

Tabetri™ (Tabebuia avellanedae Ethanol Extract) Ameliorates Osteoarthritis Symptoms Induced by Monoiodoacetate through Its Anti-Inflammatory and Chondroprotective Activities

Although osteoarthritis (OA), a degenerative joint disease characterized by the degradation of joint articular cartilage and subchondral bones, is generally regarded as a degenerative rather than inflammatory disease, recent studies have indicated the involvement of inflammation in OA pathogenesis. Tabebuia avellanedae has long been used to treat various diseases; however, its role in inflammatory response and the underlying molecular mechanisms remain poorly understood. In this study, the pharmacological effects of Tabetri (Tabebuia avellanedae ethanol extract (Ta-EE)) on OA pathogenesis induced by monoiodoacetate (MIA) and the underlying mechanisms were investigated using experiments with a rat model and in vitro cellular models. In the animal model, Ta-EE significantly ameliorated OA symptoms and reduced the serum levels of inflammatory mediators and proinflammatory cytokines without any toxicity. The anti-inflammatory activity of Ta-EE was further confirmed in a macrophage-like cell line (RAW264.7). Ta-EE dramatically suppressed the production and mRNA expressions of inflammatory mediators and proinflammatory cytokines in lipopolysaccharide-stimulated RAW264.7 cells without any cytotoxicity. Finally, the chondroprotective effect of Ta-EE was examined in a chondrosarcoma cell line (SW1353). Ta-EE markedly suppressed the mRNA expression of matrix metalloproteinase genes. The anti-inflammatory and chondroprotective activities of Ta-EE were attributed to the targeting of the nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1) signaling pathways in macrophages and chondrocytes.

Oxytocin inhibits head and neck squamous cell carcinoma cell migration by early growth response-1 upregulation

The effect of oxytocin (OXT) on cancer invasion is controversial. Few studies have examined the effect of early growth response-1 (EGR1) on the invasion of head and neck squamous cell carcinoma (HNSCC). Here, we evaluated how EGR1 affects HNSCC cell migration through the molecular mechanism of OXT in exerting anti-invasion activity. Matrigel invasion and wound-healing assays were used to measure the in-vitro cell migration. The molecular mechanism of OXT was assessed by knockdown or overexpression of EGR1 in HNSCC cells. Three-dimensional (3-D) spheroids formation, followed by the image analysis for quantification was performed. OXT at 500 nmol/l increased mRNA and protein expression of E-cadherin without cytotoxicity. OXT upregulated mRNA and protein expression of EGR1 in 6 h. p53, phosphatase and tensin, and p21 expression was increased in an EGR1-dependent manner with OXT treatment. In addition, OXT significantly downregulated 3-D spheroids' formation according to spheroids' number and size. Our data showed that OXT downregulated HNSCC cell migration by EGR1 upregulation. OXT inhibited spheroids' formation of HNSCC cells under 3-D culture conditions.

Reduction of doxorubicin-induced genotoxicity by Handroanthus impetiginosus in mouse bone marrow revealed by micronucleus assay

Handroanthus impetiginosus has long been used in traditional medicine and various studies have determined the presence of bioactive chemical compounds and potential phytotherapeutics. In this study, the genotoxicity of the lyophilized tincture of H. impetiginosus bark (THI) was evaluated in mouse bone marrow using micronucleus assays. The interaction between THI and genotoxic effects induced by the chemotherapeutic agent, doxorubicin (DXR), was also analyzed. Experimental groups were evaluated 24 to 48 h after treatment with N-nitroso-N-ethylurea (NEU; 50 mg/kg), DXR (5 mg/kg), sodium chloride (NaCl; 150 mM), and THI (0.5-2 g/kg). Antigenotoxic assays were carried out using THI (0.5 g/kg) in combination with NEU or DXR. Analysis of the micronucleated polychromatic erythrocytes (MNPCEs) indicated no significant differences between treatment doses of THI (0.5-2 g/kg) and NaCl. Polychromatic erythrocyte (PCE) to normochromatic erythrocyte (NCE) ratios did not indicate any statistical differences between DXR and THI or NaCl, but there were differences between THI and NaCl. A significant reduction in MNPCEs and PCE/NCE ratios was observed when THI was administered in combination with DXR. This study suggested the absence of THI genotoxicity that was dose-, time-, and gender-independent and the presence of moderate systemic toxicity that was dose-independent, but time- and gender-dependent. The combination of THI and DXR also suggested antigenotoxic effects, indicating that THI reduced genotoxic effects induced by chemotherapeutic agents.

β-lapachone suppresses tumour progression by inhibiting epithelial-to-mesenchymal transition in NQO1-positive breast cancers

NQO1 is a FAD-binding protein that can form homodimers and reduce quinones to hydroquinones, and a growing body of evidence currently suggests that NQO1 is dramatically elevated in solid cancers. Here, we demonstrated that NQO1 was elevated in breast cancer and that its expression level was positively correlated with invasion and reduced disease free survival (DFS) and overall survival (OS) rates. Next, we found that β-lapachone exerted significant anti-proliferation and anti-metastasis effects in breast cancer cell lines due to its effects on NQO1 expression. Moreover, we revealed that the anti-cancer effects of β-lapachone were mediated by the inactivation of the Akt/mTOR pathway. In conclusion, these results demonstrated that NQO1 could be a useful prognostic biomarker for patients with breast cancer, and its bioactivatable drug, β-lapachone represented a promising new development and an effective strategy for indicating the progression of NQO1-positive breast cancers.

β-Lapachone suppresses the lung metastasis of melanoma via the MAPK signaling pathway

β-Lapachone is a natural quinone compound from Lapacho trees, which has various pharmacological effects such as anti-bacterial, anti-fungal, anti-viral, and anti-inflammatory activities. However, the effect of β-lapachone on metastasis of melanoma cells is unclear. In this study, β-lapachone reduced cell viability of metastatic melanoma cancer cell lines B16F10 and B16BL6 through induction of apoptosis via the mitogen-activated protein kinase (MAPK) pathway. Additionally, flow cytometry results showed that β-lapachone increased DNA content in the G0/G1 phase of the cell cycle. Analysis of the mechanisms of these events indicated that β-lapachone regulated the expression of Bcl-2, Bcl-xL, and Bax, resulting in the activation of caspase-3, -8, -9, and poly-ADP-ribose polymerase (PARP). Moreover, the β-lapachone-administered group showed significantly decreased lung metastasis in the experimental mouse model. In conclusion, our study demonstrates the inhibitory effect of β-lapachone on lung metastasis of melanoma cells and provides a new insight into the role of β-lapachone as a potential antitumor agent.

β-Lapachone Inhibits Lung Metastasis of Colorectal Cancer by Inducing Apoptosis of CT26 Cells

Background: β-Lapachone is a quinone-containing compound found in red lapacho (Tabebuia impetiginosa, syn. T avellanedae) trees. Lapacho has been used in traditional medicine by several South and Central American indigenous people to treat various types of cancer. The purpose of this study was to investigate the antimetastatic properties of β-lapachone and the underlying mechanisms using colon cancer cells. Methods: This research used metastatic murine colon cancer cell lines, colon 26 (CT26) and colon 38 (MC38). A WST assay, annexin V assay, cell cycle analysis, wound healing assay, invasion assay, western blot analysis, and real-time reverse transcription–polymerase chain reaction were performed to examine the effects of β-lapachone on metastatic phenotypes and molecular mechanisms. The effect of β-lapachone on lung metastasis was assessed in a mouse experimental metastasis model. Results: We found that the inhibition of proliferation of the colon cancer cell lines by β-lapachone was due to the induction of apoptosis and cell cycle arrest. β-Lapachone induced the apoptosis of CT26 cells through caspase-3, -8, and -9 activation; poly(ADP-ribose) polymerase cleavage; and downregulation of the Bcl-2 family in a dose- and time-dependent manner. In addition, a low concentration of β-lapachone decreased the cell migration and invasion by decreasing the expression of matrix metalloproteinases-2 and -9, and increased the expression of tissue inhibitors of metalloproteinases-1 and -2. Moreover, β-lapachone treatment regulated the expression of epithelial-mesenchymal transition markers such as E- and N-cadherin, vimentin, β-catenin, and Snail in CT26 cells. In the mouse experimental metastasis model, β-lapachone significantly inhibited the lung metastasis of CT26 cells. Conclusions: Our results demonstrated the inhibitory effect of β-lapachone on colorectal lung metastasis. This compound may be useful for developing therapeutic agents to treat metastatic cancer.

Targeting EZH2-mediated methylation of H3K27 inhibits proliferation and migration of Synovial Sarcoma in vitro

Synovial sarcoma is an aggressive soft tissue sarcoma genetically defined by the fusion oncogene SS18-SSX. It is hypothesized that either SS18-SSX disrupts SWI/SNF complex inhibition of the polycomb complex 2 (PRC2) methyltransferase Enhancer of Zeste Homologue 2 (EZH2), or that SS18-SSX is able to directly recruit PRC2 to aberrantly silence target genes. This is of potential therapeutic value as several EZH2 small molecule inhibitors are entering early phase clinical trials. In this study, we first confirmed EZH2 expression in the 76% of human synovial sarcoma samples. We subsequently investigated EZH2 as a therapeutic target in synovial sarcoma in vitro. Knockdown of EZH2 by shRNA or siRNA resulted in inhibition of cell growth and migration across a series of synovial sarcoma cell lines. The EZH2 selective small-molecule inhibitor EPZ005687 similarly suppressed cell proliferation and migration. These data support the hypothesis that targeting EZH2 may be a promising therapeutic strategy in the treatment of synovial sarcoma; clinical trials are initiating enrollment currently.

β-lapachone-Induced Apoptosis of Human Gastric Carcinoma AGS Cells Is Caspase-Dependent and Regulated by the PI3K/Akt Pathway

β-lapachone is a naturally occurring quinone that selectively induces apoptotic cell death in a variety of human cancer cells in vitro and in vivo; however, its mechanism of action needs to be further elaborated. In this study, we investigated the effects of β-lapachone on the induction of apoptosis in human gastric carcinoma AGS cells. β-lapachone significantly inhibited cellular proliferation, and some typical apoptotic characteristics such as chromatin condensation and an increase in the population of sub-G1 hypodiploid cells were observed in β-lapachone-treated AGS cells. Treatment with β-lapachone caused mitochondrial transmembrane potential dissipation, stimulated the mitochondria-mediated intrinsic apoptotic pathway, as indicated by caspase-9 activation, cytochrome c release, Bcl-2 downregulation and Bax upregulation, as well as death receptor-mediated extrinsic apoptotic pathway, as indicated by activation of caspase-8 and truncation of Bid. This process was accompanied by activation of caspase-3 and concomitant with cleavage of poly(ADP-ribose) polymerase. The general caspase inhibitor, z-VAD-fmk, significantly abolished β-lapachone-induced cell death and inhibited growth. Further analysis demonstrated that the induction of apoptosis by β-lapachone was accompanied by inactivation of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. The PI3K inhibitor LY29004 significantly increased β-lapachone-induced apoptosis and growth inhibition. Taken together, these findings indicate that the apoptotic activity of β-lapachone is probably regulated by a caspase-dependent cascade through activation of both intrinsic and extrinsic signaling pathways, and that inhibition of the PI3K/Akt signaling may contribute to β-lapachone-mediated AGS cell growth inhibition and apoptosis induction.

HepG2 cells recovered from apoptosis show altered drug responses and invasiveness

BACKGROUND

Cancer relapse, associated with increased drug resistance and rate of metastasis, often follows completion of chemotherapy but the cancer escape mechanisms are still incompletely understood. Percutaneous ethanol injection (PEI) has been used for treating hepatocellular carcinoma (HCC) for decades, while the recurrence after PEI treatment remains a major limitation. Recent evidence mounted that cancer cells could survive from chemical induced apoptosis, suggesting a potential route through which cancer relapse may occur. This study focuses on the consequence of HepG2 recovery from ethanol-induced apoptotic event.

METHODS

The model of HepG2 recovery from ethanol-induced apoptotic event was established by live cell imaging, BrdU assay and Western blotting. MTT assay, wound healing assay and invasion assay were used to investigate the behavior of HepG2 after recovery.

RESULTS

HepG2 cells could recover from ethanol-induced apoptosis. These cells changed their behaviors such as drug resistance, mobility and invasiveness. On average, the recovered HepG2 cell clones were found to be 46% more resistant to ethanol and 84% higher in mobility. The recovered clones became 58.2% more sensitive to 5-fluorouracil.

CONCLUSIONS

HepG2 cells can recover from ethanol-induced apoptotic event. These cells became more resistant to ethanol and more invasive. Although the recovered cell clones were more resistant to ethanol, they became more sensitive to 5-fluorouracil treatment.

EGR1-dependent PTEN upregulation by 2-benzoyloxycinnamaldehyde attenuates cell invasion and EMT in colon cancer

There has been little evidence to support EGR1 and PTEN function on the EMT of cancer cells. We tried to evaluate how these genes affect cancer cell invasion and EMT through investigating the molecular mechanism(s) of 2'-benzoyloxycinnamaldehyde (BCA). Matrigel invasion and wound healing assay, and in vivo mice model were used to evaluate the effect of BCA on colon cancer cell migration. The molecular mechanism(s) of BCA were evaluated by knock-down or overexpression of EGR1 and PTEN. BCA at 50 nM increased E-cadherin and EGR1 expression without cytotoxicity. Cell migration was inhibited significantly by BCA both in vitro and in vivo. Moreover, BCA inhibits Snail and Vimentin expression, as well as β-catenin nuclear accumulation. Suppression of EGR1 by siRNA attenuated the inhibition of matrigel invasion by BCA, indicating that EGR1 is responsible for BCA effect. PTEN was upregulated by BCA treatment or EGR1 overexpression. In addition, shPTEN transfection stimulated EMT and cell invasion in vitro. Our data suggest that BCA leads to a remarkable upregulation of EGR1 expression, and that EMT and invasion is decreased via EGR1-dependent PTEN activation. These data showed a critical role of EGR1-PTEN signaling pathway in the EMT of colon cancer, as well as metastasis.

Bioactive phenylpropanoid glycosides from Tabebuia avellanedae

Three novel phenylpropanoid glycosides 2, 5, 6 were isolated from water extract of Tabebuia avellanedae, together with three known phenylpropanoid glycosides 1, 3, 4. All compounds were identified on the basis of spectroscopic analysis and chemical methods and, for known compounds, by comparison with published data. All isolated compounds showed strong antioxidant activity in the DPPH assay, and compound 5 give the highest antioxidant activity among all compounds, with an IC₅₀ of 0.12 µM. All compounds exhibited moderate inhibitory effect on cytochrome CYP3A4 enzyme.

Apoptosis induction of human bladder cancer cells by sanguinarine through reactive oxygen species-mediated up-regulation of early growth response gene-1

Although the effects of sanguinarine, a benzophenanthridine alkaloid, on the inhibition of some kinds of cancer cell growth have been established, the underlying mechanisms are not completely understood. This study investigated possible mechanisms by which sanguinarine exerts its anticancer action in cultured human bladder cancer cell lines (T24, EJ, and 5637). Sanguinarine treatment resulted in concentration-response growth inhibition of the bladder cancer cells by inducing apoptosis. Sanguinarine-induced apoptosis was correlated with the up-regulation of Bax, the down-regulation of Bid and XIAP, the activation of caspases (-3, -8, and -9), and the generation of increased reactive oxygen species (ROS). The ROS scavenger N-acetyl cysteine (NAC) completely reversed the sanguinarine-triggered apoptotic events. In addition, sanguinarine effectively increased the activation of the c-Jun N-terminal kinase (JNK) and the expression of the early growth response gene-1 (Egr-1), which was recovered by pretreatment with NAC. Furthermore, knockdown of Egr-1 expression by small interfering RNA attenuated sanguinarine-induced apoptosis, but not the JNK inhibitor, indicating that the interception of ROS generation blocked the sanguinarine-induced apoptotic effects via deregulation of the expression of Egr-1 proteins. Taken together, the data provide evidence that sanguinarine is a potent anticancer agent, which inhibits the growth of bladder cancer cells and induces their apoptosis through the generation of free radicals.

In vitro electrical-stimulated wound-healing chip for studying electric field-assisted wound-healing process

The wound-healing assay is an easy and economical way to quantify cell migration under diverse stimuli. Traditional assays such as scratch assays and barrier assays are widely and commonly used, but neither of them can represent the complicated condition when a wound occurs. It has been suggested that wound-healing is related to electric fields, which were found to regulate wound re-epithelialization. As a wound occurs, the disruption of epithelial barrier short-circuits the trans-epithelial potential and then a lateral endogenous electric field is created. This field has been proved invitro as an important cue for guiding the migration of fibroblasts, macrophages, and keratinocytes, a phenomenon termed electrotaxis or galvanotaxis. In this paper, we report a microfluidic electrical-stimulated wound-healing chip (ESWHC) integrating electric field with a modified barrier assay. This chip was used to study the migration of fibroblasts under different conditions such as serum, electric field, and wound-healing-promoting drugs. We successfully demonstrate the feasibility of ESWHC to effectively and quantitatively study cell migration during wound-healing process, and therefore this chip could be useful in drug discovery and drug safety tests.

Modulation of IL-2 expression after uptake of hepatitis C virus non-enveloped capsid-like particles: the role of p38 kinase

Hepatitis C virus (HCV) has been shown to actively replicate in cells of the immune system, altering both their function and cytokine expression. Naked nucleocapsids have been reported in the serum of infected patients. We investigated interference of recombinant non-enveloped capsid-like particles with signaling pathways in T cells. HCV non-enveloped particles (HCVne) internalization was verified in Jurkat and Hut 78 T cells, as well as primary human peripheral blood and intrahepatic mononuclear cells. HCVne uptake leads to activation of the MAPKs-p38 signaling pathway. Using specific phosphoantibodies, signaling pathways inhibitors, and chemical agents, it was demonstrated that p38 activation in T cells correlated with IL-2 transcriptional activation and was accompanied by a parallel increase of IL-2 cytokine secretion. c-fos and egr-1, two transcription factors, essential for IL-2 promoter activity, were also found to be elevated. We propose that HCVne uptake by T lymphocytes results in increased MAPKs-p38 activity and IL-2 expression, thus altering the host immune response.

Endocytosis of hepatitis C virus non-enveloped capsid-like particles induces MAPK-ERK1/2 signaling events

Although HCV is an enveloped virus, naked nucleocapsids have been reported in the serum of infected patients. The HCV core particle serves as a protective capsid shell for the viral genome and recombinant in vitro assembled HCV core particles induce strong specific immunity. We investigated the post-binding mechanism of recombinant core particle uptake and its intracellular fate. In hepatic cells, these particles are internalized, most likely in a clathrin-dependent pathway, reaching early to late endosomes and finally lysosomes. The endocytic acidic milieu is implicated in trafficking process. Using specific phosphoantibodies, signaling pathway inhibitors and chemical agents, ERK(1/2) was found to be activated in a sustained way after endocytosis, followed by downstream immediate early genes (c-fos and egr-1) modulation. We propose that the intriguing properties of cellular internalization of HCV non-enveloped particles can induce specific ERK(1/2)-MAPKs events that could be important in HCV life cycle and pathogenesis of HCV infection.

Antidepressant-like action of the ethanolic extract from Tabebuia avellanedae in mice: evidence for the involvement of the monoaminergic system

The antidepressant-like effect of the ethanolic extract obtained from barks of Tabebuia avellanedae, a plant widely employed in folk medicine, was investigated in two predictive models of depression: forced swimming test (FST) and tail suspension test (TST) in mice. Additionally, the mechanisms involved in this antidepressant-like action and the effects of the association of the extract with the antidepressants fluoxetine, desipramine and bupropion in the TST were investigated. The extract from T. avellanedae produced an antidepressant-like effect, in the FST (100 mg/kg, p.o.) and in the TST (10-300 mg/kg, p.o.), without accompanying changes in ambulation when assessed in the open-field test. The anti-immobility effect of the extract (30 mg/kg, p.o.) in the TST was prevented by pre-treatment of mice with ketanserin (5 mg/kg, i.p., a preferential 5-HT(2A) receptor antagonist), prazosin (1 mg/kg, i.p., an alpha(1)-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an alpha(2)-adrenoceptor antagonist), propranolol (2 mg/kg, i.p., a beta-adrenoceptor antagonist), sulpiride (50 mg/kg, i.p., a dopamine D(2) receptor antagonist) and SCH23390 (0.05 mg/kg, s.c., a dopamine D(1) receptor antagonist). The combined administration of a subeffective dose of WAY100635 (0.1 mg/kg, s.c., a selective 5-HT(1A) receptor antagonist) and a subeffective dose of the extract (1 mg/kg, p.o.) produced a significant reduction in the immobility time in the TST. In addition, the combination of fluoxetine (1 mg/kg, p.o.), desipramine (0.1 mg/kg, p.o.), or bupropion (1 mg/kg, p.o.) with a subeffective dose of the extract (1 mg/kg, p.o.) produced a synergistic antidepressant-like effect in the TST, without causing hyperlocomotion in the open-field test. It may be concluded that the extract from T. avellanedae produces an antidepressant-like effect in the FST and in the TST that is dependent on the monoaminergic system. Taken together, our results suggest that T. avellanedae deserves further investigation as a putative alternative therapeutic tool that could help the conventional pharmacotherapy of depression.

Thalidomide inhibits leukemia cell invasion and migration by upregulation of early growth response gene 1

Thalidomide has been shown to exert its antitumor activity through the significant effects on microenvironment and immunomodulatory properties. In this study, 10 microM thalidomide treatment markedly increased the expression of the early growth response gene 1 (Egr-1) at both mRNA and protein levels in HL-60 leukemic cells. Thalidomide treatment significantly decreased the invasive cells number through Matrigel and human umbilical vein endothelial cells when compared with the controls. Moreover, the inhibitory effects could be markedly abolished by Egr-1 gene silencing with siRNA technology. Our data indicated thalidomide could suppress leukemia cell invasion and migration by upregulation of Egr-1, suggesting a novel mechanism of thalidomide in the treatment of leukemia. Further investigations are needed to explore the detailed mechanism of Egr-1 induction by thalidomide and the downstream pathways involved in the regulation of leukemia cell invasion.

In vitro and in vivo anti-inflammatory effects of taheebo, a water extract from the inner bark of Tabebuia avellanedae

AIM OF STUDY

Tabebuia spp. (Bignoniaceae) are native to tropical rain forests throughout Central and South America and have long been used as a folk medicine to treat bacterial infection, blood coagulation, cancer and inflammatory diseases. In this study, we aimed to demonstrate the ethnopharmacological activity of Tabebuia avellanedae in various in vitro and in vivo inflammatory conditions.

MATERIALS AND METHODS

To do this, LPS-stimulated macrophages and arachidonic acid or croton oil-induced mouse ear edema models were employed.

RESULTS

The water extract (taheebo) of Tabebuia avellanedae significantly suppressed the production of prostaglandin (PG) E(2) and nitric oxide (NO), and blocked the mRNA expression of their catalyzing enzymes (cyclooxygenase [COX)-II] and inducible NO synthase [iNOS], respectively), in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The blockade of inflammatory mediators by taheebo seemed to be the result of the interruption of extracellular signal-related kinase (ERK) activation, according to immunoblotting analysis and the NO assay, where LPS strongly induced the phosphorylation (a hallmark of activation) of ERK, and U0126, a selective ERK inhibitor, was found to strongly inhibit PGE(2) production. Similarly, oral administration of taheebo (100mg/kg) for 1 week completely diminished mouse ear edema induced by arachidonic acid, an activator of COX-II, but not croton oil, an activator of lipoxygenase.

CONCLUSIONS

These data suggest that the ethnopharmacological action of taheebo may be due to its negative modulation of macrophage-mediated inflammatory responses by suppressing PGE(2) production. Thus, this water extract may be developed as a new therapeutic remedy for various inflammatory diseases such as arthritis and atherosclerosis.

Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1alpha) upregulated E-cadherin expression in HepG2 cells

Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1alpha), a highly inducible transcriptional coactivator regulating energy homeostasis, is down-regulated in hepatoma tissues. To dissect its role in hepato-tumorigenesis, Ingenuity Pathway Analysis was applied to construct pathways affected by PGC-1alpha upregulation in HepG2 hepatoma cells based on our microarray data. Interestingly, migration of these cells was markedly diminished by PGC-1alpha overexpression in consistency with Ingenuity results. Moreover, a deduced expression increase of E-cadherin was also observed in PGC-1alpha-overexpressing HepG2 cells. Finally, transient transfection and chromatin-immunoprecipitation assays suggested that increased histone acetylation might be responsible for PGC-1alpha-mediated transactivation of a minimal E-cadherin promoter.