Sonic hedgehog pathway promotes metastasis and lymphangiogenesis via activation of Akt, EMT, and MMP-9 pathway in gastric cancer

Hedgehog pathway aberrations and gastric cancer; evaluation of prognostic impact and exploration of therapeutic potentials

Gastric cancer is an important cause for mortality and morbidity worldwide; it lies in the fourt rank as a cause of cancer-related death in males and in the fifth rank of cancer-related death in women. The prognosis of advanced/metastatic gastric cancer cases looks poor with the majority of available therapeutics. Thus, novel therapeutic strategies in this setting have been considered a priority for leading cooperative oncology groups. Hedgehog(Hh) pathway aberrations have sparked particular interest as prognostic markers with data from multiple studies showing consistent evidence of a poor prognostic value of Gli over expression in gastric cancer while on the other hand the prognostic significance of Hh protein over expression (particularly SHH) was not consistent among different studies. This review article revises the prognostic and potential therapeutic opportunities in the targeting of hedgehog pathway in gastric cancer.

Cooperative integration between HEDGEHOG-GLI signalling and other oncogenic pathways: implications for cancer therapy

The HEDGEHOG-GLI (HH-GLI) signalling is a key pathway critical in embryonic development, stem cell biology and tissue homeostasis. In recent years, aberrant activation of HH-GLI signalling has been linked to several types of cancer, including those of the skin, brain, lungs, prostate, gastrointestinal tract and blood. HH-GLI signalling is initiated by binding of HH ligands to the transmembrane receptor PATCHED and is mediated by transcriptional effectors that belong to the GLI family, whose activity is finely tuned by a number of molecular interactions and post-translation modifications. Several reports suggest that the activity of the GLI proteins is regulated by several proliferative and oncogenic inputs, in addition or independent of upstream HH signalling. The identification of this complex crosstalk and the understanding of how the major oncogenic signalling pathways interact in cancer is a crucial step towards the establishment of efficient targeted combinatorial treatments. Here we review recent findings on the cooperative integration of HH-GLI signalling with the major oncogenic inputs and we discuss how these cues modulate the activity of the GLI proteins in cancer. We then summarise the latest advances on SMO and GLI inhibitors and alternative approaches to attenuate HH signalling through rational combinatorial therapies.

Inhibition of metastasis and growth of breast cancer by pH-sensitive poly (β-amino ester) nanoparticles co-delivering two siRNA and paclitaxel

Breast cancer is the most vicious killer for women's health, while metastasis is the main culprit, which leads to failure of treatment by increasing relapse rate. In this work, a new complexes nanoparticles loading two siRNA (Snail siRNA (siSna) and Twist siRNA (siTwi)) and paclitaxel (PTX) were designed and constructed using two new amphiphilic polymer, polyethyleneimine-block-poly[(1,4-butanediol)-diacrylate-β-5-hydroxyamylamine] (PEI-PDHA) and polyethylene glycol-block-poly[(1,4-butanediol)-diacrylate-β-5-hydroxyamylamine] (PEG-PDHA) by self-assembly. The experimental results showed that in the 4T1 tumor-bearing mice models, PEI-PDHA/PEG-PDHA/PTX/siSna/siTwi) complex nanoparticles (PPSTs) raised the accumulation and retention of both PTX and siRNA in tumor after administrated intravenously, resulted in the strong inhibition of the tumor growth and metastasis simultaneously. It was found that co-delivery of siSna and siTwi had more significant anti-metastasis effect than delivering a single siRNA, as a result of simultaneously inhibiting the motility of cancer cells and degradation of ECM. Therefore, PPSTs could be a promising co-delivery vector for effective therapy of metastatic breast cancer.

MIR210 as a potential molecular target to block invasion and metastasis of gastric cancer

The epithelial-mesenchymal transition (EMT) is a process driving invasion, recurrence, and metastasis of gastric cancer, and EMT is triggered by specific physiological factors that arise during tumorigenesis, such as hypoxia. Identifying the molecular mechanisms underlying EMT will potentially yield insight into the pathways fueling cancer recurrence and metastasis and thus, lead to novel molecular targets that will improve treatment of the disease. The microRNA210 (MIR210) is such a candidate molecule mediating EMT in gastric cancer based on a number of observations. First, MIR210 is often highly overexpressed in gastric cancer. Second, MIR210 is a hypoxia-specific miRNA, and its expression is significantly increased in hypoxic environments where EMT develops. Third, MIR210 is regulated by hypoxia inducible factor 1α (HIF-1α), a key transcription factor mediating important tumor associated processes such as EMT and angiogenesis in response to hypoxia during tumorigenesis. Finally, MIR210 has been intriguingly associated with Helicobacterpylori infection, which typically develops in an anaerobic environment and is known to have a causal role in the development of gastric cancer. Although studies have shown that MIR210 is often highly expressed in gastric cancer and associated with specific pathological conditions, functional experiments have not yet been performed to determine the role of MIR210 and downstream mediators in the development and progression of gastric cancer. Here, MIR210 is proposed as a viable molecular target in the treatment of gastric cancer, specifically for the inhibition of invasion and metastasis.

Transcription factor glioma-associated oncogene homolog 1 is required for transforming growth factor-β1-induced epithelial-mesenchymal transition of non-small cell lung cancer cells

Epithelial-mesenchymal transition (EMT) is the process by which epithelial cells depolarize and acquire a mesenchymal phenotype, and is a common early step in the process of metastasis. Patients with lung cancer frequently already have distant metastases when they are diagnosed, highlighting the requirement for early and effective interventions to control metastatic disease. Transforming growth factor-β1 (TGF-β1) is able to induce EMT, however the molecular mechanism of this remains unclear. In the current study, TGF-β1 was reported to induce EMT and promote the migration of non-small cell lung cancer (NSCLC) cells. A notable observation was that EMT induction was accompanied by the upregulation of human glioma-associated oncogene homolog 1 (Gli1) mRNA and protein levels. Furthermore, Gli1 levels were depleted by small interfering RNA, and the Gli1 inhibitor GANT 61 attenuated the TGF-β1-mediated induction of EMT and cell migration. The results of the current study suggest that Gli1 regulates TGF-β1-induced EMT, which may provide a novel therapeutic target to inhibit metastasis in patients with NSCLC.

Overexpression of twist and matrix metalloproteinase-9 with metastasis and prognosis in gastric cancer

OBJECTIVE

Twist, a basic helix-loop-helix transcription factor, plays a key role in the metastatic progression of human cancer. Matrix metalloproteinase (MMP)-9 is an endopeptidase that digests basement membrane type IV collagen, therefore being possibly related to tumor progression. It has been reported that Twist and matrix metalloproteinase-9 (MMP-9) are expressed in gastric cancers. However, the exact roles of Twist and MMP-9 in tumor metastasis and prognosis remain unclear. The aim of this study was to casts light on this question.

METHODS

Twist and MMP-9 expression in tissue sections of 37 gastric carcinomas was evaluated with immunohistochemistry. The staining results were compared with clinicopathologic features and to patients'outcome.

RESULTS

Twist positive expression was significantly increased in gastric cancer cases with lymph node metastasis (P=0.023). But no correlations were found between MMP-9 overexpression and clinicopathologic features, such as recurrence, TNM stage, and lymph node metastasis. Overall survival (OS) was significantly correlated with recurrence, serosa invasion, TNM stages, distant metastasis, and MMP-9 (P=0.027, 0.021, 0.000, 0.024 and 0.036, respectively). Disease-free survival (DFS) was prominently related to recurrence location, serosa invasion and TNM stages (P=0.000, 0.038 and 0.003, respectively). In the Cox regression multivariate analysis, TNM stage, distant metastasis and MMP-9 were significantly associated with prognosis of gastric cancer (P=0.002, 0.019, and 0.032, respectively).

CONCLUSIONS

This study showed Twist positive expression to be significantly correlated with lymph node metastasis in gastric cancer. MMP-9 overexpression is associated with OS, suggesting that MMP-9 is a prognostic indicator for survival in patients with gastric cancer.

Smoking-induced changes in cancer-related factors in patients with upper tract urothelial cancer

Cigarette smoking is a major risk factor for urothelial cancer (UC) development. However, the associations between smoking and changes in the pathological characteristics and molecular expression of cancer-related molecules in upper tract (UT) UC have not been fully elucidated. We investigated the associations between smoking status and cancer-related factors, including cancer cell proliferation, apoptosis, angiogenesis, lymphangiogenesis and expression of vascular endothelial growth factor-A and -C, matrix metalloproteinase (MMP)-2 and -9, cyclooxygenase (COX)-2 and urokinase-type plasminogen activator, in patients with UTUC. A total of 134 patients who underwent nephroureterectomy were retrospectively investigated. Proliferation index (PI), microvessel density and lymphatic vessel density (LVD) were measured using anti-Ki-67, anti-CD105 and anti-D2-40 antibodies in formalin-fixed specimens. The apoptotic index was evaluated using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method. Other cancer-related molecules were investigated by immunohistochemistry in similar specimens. The patients were divided into three groups; non-smoker (n=54, 40.3%), former smoker (n=46, 34.3%) and current smoker (n=34, 25.4%). The PI and the apoptotic index were not found to be correlated with smoking status; however, the mean/standard deviation level of LVD in current smokers (40.9/12.9) was significantly higher (P=0.034) compared to that in patients who had never smoked (34.4/10.6). In addition, smoking status was positively correlated with the presence of intratumoral lymphatic vessels (iLV) (P=0.010) and the expression of COX-2 and MMP-9 (P=0.032). The multivariate analysis demonstrated that current smoking was independently associated with all the abovementioned smoking-related factors. However, former smoking was correlated with LVD and the presence of iLV. In the survival analysis, LVD, the presence of iLV and the expression of COX-2 and MMP-9 were identified as predictive factors for metastasis following surgery. In conclusion, lymphangiogenesis and the expression levels of COX-2 and MMP-9 were found to be associated with the smoking status of UTUC patients. Our results may provide important insights into the pathological changes precipitated by smoking in these patients.

SMO expression in colorectal cancer: associations with clinical, pathological, and molecular features

BACKGROUND

Smoothened, frizzled family receptor (SMO) is an important component of the hedgehog signaling pathway, which has been implicated in various human carcinomas. However, clinical, molecular, and prognostic associations of SMO expression in colorectal cancer remain unclear.

METHODS

Using a database of 735 colon and rectal cancers in the Nurse's Health Study and the Health Professionals Follow-up Study, we examined the relationship of tumor SMO expression (assessed by immunohistochemistry) to prognosis, and to clinical, pathological, and tumor molecular features, including mutations of KRAS, BRAF, and PIK3CA, microsatellite instability, CpG island methylator phenotype (CIMP), LINE-1 methylation, and expression of phosphorylated AKT and CTNNB1.

RESULTS

SMO expression was detected in 370 tumors (50 %). In multivariate logistic regression analysis, SMO expression was independently inversely associated with phosphorylated AKT expression [odds ratio (OR) 0.48; 95 % confidence interval (CI) 0.34-0.67] and CTNNB1 nuclear localization (OR 0.48; 95 % CI 0.35-0.67). SMO expression was not significantly associated with colorectal cancer-specific or overall survival. However, in CIMP-high tumors, but not CIMP-low/0 tumors, SMO expression was significantly associated with better colorectal cancer-specific survival (log-rank P = 0.012; multivariate hazard ratio, 0.36; 95 % CI 0.13-0.95; P interaction = 0.035, for SMO and CIMP status).

CONCLUSIONS

Our data reveal novel potential associations between the hedgehog, the WNT/CTNNB1, and the PI3K (phosphatidylinositol-4,5-bisphosphonate 3-kinase)/AKT pathways, supporting pivotal roles of SMO and hedgehog signaling in pathway networking. SMO expression in colorectal cancer may interact with tumor CIMP status to affect patient prognosis, although confirmation by future studies is needed.

Doxycycline inhibits inflammation-induced lymphangiogenesis in mouse cornea by multiple mechanisms

Lymphangiogenesis is significantly involved in the pathogenesis of diseases, including graft rejection, cancer metastasis and various inflammatory conditions. The inhibition of lymphangiogenesis has become a new therapeutic target for the treatment of these diseases. Here, we explored the anti-lymphangiogenic effects of doxycycline in inflammation-induced lymphangiogenesis (ILA) in the cornea and the underlying mechanisms. In the present study, mice with ILA of the cornea were treated with topical doxycycline (0.1%) or vehicle control. Lymphangiogenesis was quantified using corneal immunostaining of lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1). Human dermal lymphatic endothelial cells (HDLECs) and a murine macrophage cell line (RAW264.7) were used to further explore the underlying mechanisms of doxycycline-mediated anti-lymphangiogenesis in vitro. Our results showed that doxycycline treatment dramatically inhibited ILA in the mouse cornea (p<0.001), with a significant decrease in vascular endothelial growth factor (VEGF)-C/VEGF receptor 3 signalling, macrophage infiltration and inflammatory cytokine expression. Doxycycline also significantly inhibited VEGF-C-induced HDLEC proliferation in vitro by modulating the PI3K/Akt/endothelial nitric oxide (NO) synthase (eNOS) pathway and significantly suppressed interleukin-1β (IL-1β), TNF-α and VEGF-C production in the RAW264.7 cell line by modulating the PI3K/Akt/nuclear factor-kappaB (NF-κB) pathway. Additionally, doxycycline treatment dramatically reduced the phosphorylation of NF-κBp65, Akt and eNOS in ILA and significantly inhibited matrix metalloproteinases (MMPs) activity in vitro and in ILA. In conclusion, doxycycline inhibited ILA, possibly through suppression of VEGF-C signalling, macrophage function and MMPs activity. This observation suggests that doxycycline is a potential therapeutic agent for lymphangiogenesis-related diseases.

Signaling pathway cooperation in TGF-β-induced epithelial-mesenchymal transition

Transdifferentiation of epithelial cells into cells with mesenchymal properties and appearance, that is, epithelial-mesenchymal transition (EMT), is essential during development, and occurs in pathological contexts, such as in fibrosis and cancer progression. Although EMT can be induced by many extracellular ligands, TGF-β and TGF-β-related proteins have emerged as major inducers of this transdifferentiation process in development and cancer. Additionally, it is increasingly apparent that signaling pathways cooperate in the execution of EMT. This update summarizes the current knowledge of the coordination of TGF-β-induced Smad and non-Smad signaling pathways in EMT, and the remarkable ability of Smads to cooperate with other transcription-directed signaling pathways in the control of gene reprogramming during EMT.

Resveratrol inhibits epithelial-mesenchymal transition and renal fibrosis by antagonizing the hedgehog signaling pathway

Epithelial-to-mesenchymal transition (EMT), a biologic process in which tubular cells lose their epithelial phenotypes and acquire new characteristic features of mesenchymal properties, is increasingly recognized as an integral part of renal tissue fibrogenesis. Recent studies indicate that resveratrol, a botanical compound derived mainly from the skins of red grapes, may have anti-fibrotic effects in many tissues, but the potential molecular mechanism remains unknown. In the present study, we identified that resveratrol inhibits the induction of EMT and deposition of extracellular matrix (ECM) through antagonizing the hedgehog pathway in vitro and in vivo. In rats with unilateral ureteral obstruction (UUO), administration of resveratrol (20mg/kg/day) significantly reduced serum creatinine. Resveratrol also decreased expression of TGF-β1, and inhibited the phenotypic transition from epithelial cells to mesenchymal cells, and the deposition of ECM in UUO rats. In cultured renal tubular epithelial cells (NRK-52E), TGF-β1-induced EMT and ECM synthesis was abolished with the treatment of resveratrol. The induction of EMT was associated with the activation of the hedgehog pathway. Resveratrol treatment markedly inhibited the over-activity of the hedgehog pathway in the obstructed kidney and in TGF-β1-treated NRK-52E cells, resulted in reduction of cellular proliferation, EMT and ECM accumulation. Thus, these results suggest that resveratrol is able to inhibit EMT and fibrosis in vivo and in vitro through antagonizing the hedgehog pathway, and resveratrol may have therapeutic potential for patients with fibrotic kidney diseases.

Sonic hedgehog signaling in Basal cell nevus syndrome

The hedgehog (Hh) signaling pathway is considered to be a major signal transduction pathway during embryonic development, but it usually shuts down after birth. Aberrant Sonic hedgehog (Shh) activation during adulthood leads to neoplastic growth. Basal cell carcinoma (BCC) of the skin is driven by this pathway. Here, we summarize information related to the pathogenesis of this neoplasm, discuss pathways that crosstalk with Shh signaling, and the importance of the primary cilium in this neoplastic process. The identification of the basic/translational components of Shh signaling has led to the discovery of potential mechanism-driven druggable targets and subsequent clinical trials have confirmed their remarkable efficacy in treating BCCs, particularly in patients with nevoid BCC syndrome (NBCCS), an autosomal dominant disorder in which patients inherit a germline mutation in the tumor-suppressor gene Patched (Ptch). Patients with NBCCS develop dozens to hundreds of BCCs due to derepression of the downstream G-protein-coupled receptor Smoothened (SMO). Ptch mutations permit transposition of SMO to the primary cilium followed by enhanced expression of transcription factors Glis that drive cell proliferation and tumor growth. Clinical trials with the SMO inhibitor, vismodegib, showed remarkable efficacy in patients with NBCCS, which finally led to its FDA approval in 2012.

Effect of Helicobacter pylori lipopolysaccharide on expression of Ptch-1 and Gli proteins in gastric cancer AGS cells

AIM: To explore the expression of Ptch-1 and Gli, two members in the sonic hedgehog (Shh) signaling pathway, in gastric cancer AGS cells after stimulation with Helicobacter pylori (H. pylori) lipopolysaccharide (LPS) and cyclopamine.

METHODS: Different concentrations of H. pylori LPS were used to stimulate AGS cells for 24 h, and the expression of Ptch-1 and Gli was assayed by Western blot to find the optimal stimulation concentration. AGS cells were then treated with H. pylori LPS at the optimal concentration for 24, 48 and 72 h, and the expression of Ptch-1 and Gli was detected by Western blot. MTT assay was applied to explore the effect of cyclopamine on AGS cell proliferation, and the half maximal inhibitory concentration (IC₅₀) was calculated. AGS cells were then treated with cyclopamine at IC₅₀ for 24, 48 and 72 h, and the expression of Ptch-1 and Gli was detected by Western blot. AGS cells were divided into three groups and stimulated with H. pylori LPS, cyclopamine and H. pylori LPS plus cyclopamine for 24 h, respectively, and the expression of Ptch-1 and Gli was then detected by Western blot.

RESULTS: After different concentrations of H. pylori LPS were used to stimulate AGS cells for 24 h, the expression of Ptch-1 and Gli was increased (P < 0.05) and eventually reached a plateau. After treatment of AGS cells with H. pylori LPS at the optimal concentration for 24, 48 and 72 h, the expression of Ptch-1 and Gli was increased in a time dependent manner (P < 0.05). After treatment of AGS cells with different concentrations of cyclopamine for 24 h, the proliferation of AGS cells was inhibited in a concentration dependent manner (P < 0.05). Treatment with cyclopamine at IC₅₀ decreased the expression of Gli in a time dependent manner (P < 0.05), but showed no significant effect on expression of Ptch-1 (P > 0.05). The expression of Ptch-1 in the H. pylori LPS plus cyclopamine group was significantly higher than that in the control group and cyclopamine group (P < 0.05), but was not significantly different from that in the H. pylori LPS group (P > 0.05). The expression of Gli in the H. pylori LPS plus cyclopamine group was significantly lower than that in the control group and H. pylori LPS group (P < 0.05), but was not significantly different from that in the cyclopamine group (P > 0.05).

CONCLUSION: H. pylori may alter the expression of components of the Shh signaling pathway through its virulence factor LPS in AGS cells. Cyclopamine can inhibit the growth of AGS cells by inhibition of the Shh signaling pathway. H. pylori LPS may play a role by influencing the upstream molecules of the Shh signaling pathway.

The effects of sonic hedgehog signaling pathway components on non-small-cell lung cancer progression and clinical outcome

Background

Researchers in recent studies have reported that the sonic hedgehog (Shh) signaling pathway plays a crucial role during tumorigenesis, angiogenesis and cellular differentiation. We investigated the clinical and pathological significances of the Shh pathway and of its lymphangiogenic components in non-small-cell lung cancer (NSCLC), namely, Shh, glioma-associated oncogene homolog zinc finger protein 1 (Gli1), lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) and vascular endothelial growth factor D (VEGF-D).

Methods

The expression of Shh, Gli1, LYVE-1 and VEGF-D in primary NSCLC tissue from 40 patients was examined using immunohistochemical assays, and relationships between expression and clinicopathological data, such as age, gender, histology, tumor size, nodal stage, visceral pleural invasion, lymphatic thromboembolism, recurrence and overall survival were investigated.

Results

Of the 40 specimens examined, 25 (62.5%), 20 (50.0%), 11 (27.5%) and 20 (50.0%) were positive for Shh, Gli1, LYVE-1 or VEGF-D expression, respectively. The expression of Gli1 and LYVE-1 were significantly associated (P = 0.011), and Shh and LYVE-1 expression was related to visceral pleural invasion and lymphatic thromboembolism, respectively (P < 0.05). Shh expression levels compared on survival curves were statistically significant in univariate logrank analysis (P = 0.020). However, other clinicopathological factors did not reveal any statistical significance in univariate and multivariate analyses.

Conclusions

To our knowledge, this the first report of the relationship between components of the Shh signaling pathway and prognosis in NSCLC. The expression of Shh, Gli1 and LYVE-1 was found to be associated with clinicopathological factors and survival. Thus, the overexpression of the Shh signaling pathway could serve as a predictor of malignant behavior, including lymphangiogenesis, in NSCLC.

Implications of stemness-related signaling pathways in breast cancer response to therapy

There is accumulating evidence that breast cancer may arise from a small subpopulation of transformed mammary stem/progenitor cells, termed breast cancer-initiating cells (BCICs), responsible for initiation and maintenance of cancer. BCICs have been identified in clinical specimens based on CD44(+)/CD24(-/low) membrane expression and/or enzymatic activity of aldehyde dehydrogenase 1 (ALDH1+), or isolated and in vitro propagated as non-adherent spheres. This cell population has been demonstrated to be able to recreate, when injected in mice even at very low concentrations, the same histopathological features of the tumor they were derived from and to escape from current therapeutic strategies. Alterations in genes involved in stemness-related pathways, such as Wnt, Notch, and Sonic Hedgehog, have been proven to play a role in breast cancer progression. Targeting these key elements represents an attractive option, with a solid rationale, although possible concerns may derive from the poor knowledge of tolerance and efficacy of inhibiting these mechanisms without inducing severe side effects. In addition, efforts to develop alternative BCIC-targeted therapies against stemness markers (CD44 and ALDH1) and molecules involved in regulating EMT- and HER2-related pathways, or able to reverse the multi-drug resistance phenotype, or to induce differentiation and to control cell survival pathways are currently ongoing and encouraging results from pre-clinical studies have already been obtained using in vitro and in vivo models.

Emerging role of mucins in epithelial to mesenchymal transition

Epithelial to mesenchymal transition (EMT) is an important and complex phenomenon that determines the aggressiveness of cancer cells. The morphological transformation of cancerous cells is accompanied by various cellular processes such as alterations in cell-cell adhesion, cell matrix degradation, down regulation of epithelial marker Ecadherin and upregulation of mesenchymal markers N-cadherin and Vimentin. Besides these markers several other important tumor antigens/mucins are also involved in the EMT process. Mainly high molecular weight glycoproteins such as mucin molecules (MUC1, MUC4 and MUC16) play a major role in the cellular transformation and signaling alteration in EMT process. In addition to these factors, EMT may be an essential process triggering the emergence or expansion of the CSC population, which slowly results in the initiation of tumor at metastatic sites. Furthermore, mucins have been demonstrated to be involved in the EMT process and also in the enrichment of cancer stem cell population. Mucin mediated EMT is very complex since the key components of tumor microenvironment are also regulating mucin molecules. In this review, we have discussed all the aforementioned factors and their mechanistic involvement for EMT process.

From sprouting angiogenesis to erythrocytes generation by cancer stem cells: evolving concepts in tumor microcirculation

Angiogenesis is essential for tumor growth and metastasis. Over the last decades, a substantial progress has been achieved in defining different patterns of tumor microcirculation. Sprouting angiogenesis, the oldest model of microcirculation, is the de novo vessel formation from preexisting blood vessels. Vessel splitting and hijacking, also known, respectively, as intussusception and cooption, are alternative models that account for tumor resistance to antiangiogenic therapy. In addition to remodeling the microenvironment, the tumor cell can undergo intrinsic changes and survive hypoxic conditions by acquiring stem cell properties. In line with the concept of pluripotency, tumor cells can form vascular mimicry structures creating their own microcirculation despite a latent vessel growth. The recent identification of the polyploid giant cancer cells and tumor-derived erythrocytes is the most innovative survival mechanism in hypoxia and provides a potential target for more effective therapies.

Activation of phosphatidylinositol 3-kinase/Akt signaling mediates sorafenib-induced invasion and metastasis in hepatocellular carcinoma

Sorafenib, an antiangiogenic agent, can promote tumor invasion and metastasis. The phosphatidylinositol 3-kinase (PI3K)/Akt/Snail-dependent pathway plays an important role in tumor invasion and metastasis. Yet, little is known concerning the role of the PI3K/Akt/Snail-dependent pathway in sorafenib‑induced invasion and metastasis of hepatic carcinoma (HCC). A human HCC orthotopic xenograft model was established, and sorafenib (30 mg/kg/day) was administered orally. Tumor growth and intrahepatic metastasis were assessed, and immunohistochemistry was applied to analyze the activation of the PI3K/Akt/Snail-dependent pathway. HCC cell lines were treated with sorafenib (1, 5 and 10 µM), and proliferation, migration and invasion were assessed. Western blotting and real-time polymerase chain reaction (RT-PCR) were used to examine the related gene expression of epithelial-mesenchymal transition (EMT) markers and the PI3K/Akt/Snail-dependent pathway. Sorafenib inhibited tumor growth and promoted intrahepatic invasion and metastasis of the orthotopic tumors grown from SMMC7721-GFP cells in vivo. Additionally, sorafenib promoted EMT and invasion and metastasis of HCC cells in vitro. Importantly, sorafenib enhanced PI3K and Akt activation and upregulation of the expression of transcription factor Snail, a critical EMT mediator. The upregulation of transcription factor Snail expression by sorafenib may be related to activation of the PI3K/AKT signaling pathway. The PI3K/Akt/Snail-dependent pathway may mediate the pro-invasive and pro-metastatic effects of sorafenib on HCC by inducing EMT.

Targeting EMT in cancer: opportunities for pharmacological intervention

The spread of cancer cells to distant organs represents a major clinical challenge in the treatment of cancer. Epithelial-mesenchymal transition (EMT) has emerged as a key regulator of metastasis in some cancers by conferring an invasive phenotype. As well as facilitating metastasis, EMT is thought to generate cancer stem cells and contribute to therapy resistance. Therefore, the EMT pathway is of great therapeutic interest in the treatment of cancer and could be targeted either to prevent tumor dissemination in patients at high risk of developing metastatic lesions or to eradicate existing metastatic cancer cells in patients with more advanced disease. In this review, we discuss approaches for the design of EMT-based therapies in cancer, summarize evidence for some of the proposed EMT targets, and review the potential advantages and pitfalls of each approach.

miR-942 decreases TRAIL-induced apoptosis through ISG12a downregulation and is regulated by AKT

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an attractive death ligand in targeted cancer therapy. Many cancer cells are refractory to TRAIL-induced cell death and the mechanisms underlying resistance are unclear. The molecular mechanisms of HCC and gastric cancer cells resistant to TRAIL-induced apoptosis were explored using molecular biological and immunological methods. In vivo experiments were conducted to study the effect of interferon stimulated gene 12a (ISG12a) on human liver cancer xenografts in mice. ISG12a decreases in TRAIL-resistant cancer cells. ISG12a regulates the sensitivity of cancer cells to TRAIL in vitro and in vivo. MicroRNA-942 (miR-942) is inversely correlated with ISG12a expression in cancer cells and tissues. Forced expression of miR-942 in TRAIL-sensitive cells significantly reduces endogenous ISG12a level and changes the TRAIL sensitive phenotype to a resistant one. Knockdown of miR-942 expression in TRAIL-resistant cells restores the expression of ISG12a and sensitizes the cells to TRAIL treatment. AKT control TRAIL resistance of cancer cells through downregulation of ISG12a by miR-942. Downregulation of ISG12a by miR-942 is needed to maintain the TRAIL-resistant phenotype of cancer cells and favors cancer cell survival. MiR-942 may offer a novel drug response marker with important implications in designing new therapeutics for TRAIL resistant tumors.

Transfection with small interfering RNA targeting smoothened promotes cell apoptosis in human esophageal carcinoma cell line CAES-17

AIM: To investigate the effect of transfection with small interfering RNA (siRNA) targeting smoothened (Smo) on the expression of Bcl-2 in esophageal cancer CAES-17 cells.

METHODS: Smo siRNA was transfected into CAES-17 cells. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect the levels of Smo and Bcl-2 mRNAs and proteins. TUNEL assay and flow cytometry were used to detect cell apoptosis.

RESULTS: Compared with the control groups, after transfection with Smo siRNA for 24, 48 and 72 h, the levels of Smo mRNA were significantly down-regulated (0.524 ± 0.011, 0.422 ± 0.008, 0.332 ± 0.019, P < 0.05 for all). After transfection with Smo siRNA for 72 h, the levels of Smo and Bcl-2 proteins were also significantly lower compared with the control groups (0.330 ± 0.016, 0.391 ± 0.019, P < 0.05 for all). The number of apoptotic cells was greatly increased after Smo siRNA transfection.

CONCLUSION: Smo gene may play an important role in the apoptosis of esophageal cancer cells. Smo may be used as a novel biomarker for the treatment of esophageal carcinoma.

Clinical significance of epithelial-mesenchymal transition

The concept of epithelial-mesenchymal transition (EMT), a process where cells change their epithelial towards a mesenchymal phenotype, has gained overwhelming attention especially in the cancer research community. Thousands of scientific reports investigated changes in gene, mRNA and protein expression compatible with EMT and their possible correlation with tumor invasion, metastatic spread or patient prognosis; however, up to now, a proof of clinical significance of the concept is still missing. This review, with a main focus on the role of EMT in tumors, will summarize the basic molecular events underlying EMT including the signaling pathways capable of its induction as well as changes in EMT-associated protein expression and will very briefly touch the role of microRNAs in EMT. We then outline protein markers that are used most frequently for the assessment of EMT in research and diagnostic evaluation of tumor specimens and depict the link between EMT, a cancer stem cell (CSC) phenotype and resistance to conventional antineoplastic therapies. Furthermore, we evaluate a possible correlation between EMT marker expression and patient prognosis as well as current therapeutic concepts targeting the EMT process to slow down or prevent metastatic spread of malignant tumors.

A complex mechanism for HDGF-mediated cell growth, migration, invasion, and TMZ chemosensitivity in glioma

HDGF is overexpressed in gliomas as compared to normal brain. We therefore analyzed the molecular mechanisms of HDGF action in gliomas. HDGF was downregulated in normal brain tissue as compared to glioma specimens at both the mRNA and the protein levels. In glioma samples, increased HDGF expression was associated with disease progression. Knocking down HDGF expression not only significantly decreased cellular proliferation, migration, invasion, and tumorigenesis, but also markedly enhanced TMZ-induced cytotoxicity and apoptosis in glioma cells. Mechanistic analyses revealed that CCND1, c-myc, and TGF-β were downregulated after stable HDGF knockdown in the U251 and U87 glioma cells. HDGF knockdown restored E-cadherin expression and suppressed mesenchymal cell markers such as vimentin, β-catenin, and N-cadherin. The expression of cleaved caspase-3 increased, while Bcl-2 decreased in each cell line following treatment with shHDGF and TMZ, as compared to TMZ alone. Furthermore, RNAi-based knockdown study revealed that HDGF is probably involved in the activation of both the PI3K/Akt and the TGF-β signaling pathways. Together, our data suggested that HDGF regulates glioma cell growth, apoptosis and epithelial-mesenchymal transition (EMT) probably through the Akt and the TGF-β signaling pathways. These results provide evidence that targeting HDGF or its downstream targets may lead to novel therapies for gliomas.

Interaction between gastric cancer stem cells and the tumor microenvironment

Gastric cancer (GC) remains a leading cause of cancer-related deaths worldwide. Cancer stem cells (CSCs) are selectively capable of tumor initiation and are implicated in tumor relapse and metastasis, thus, governing the prognosis of GC patients. Stromal cells and extracellular matrix adjacent to cancer cells are known to form a supportive environment for cancer progression. CSC properties are also regulated by their microenvironment through cell signaling and related factors. This review presents the current findings regarding the influence of the tumor microenvironment on GC stem cells, which will support the development of novel therapeutic strategies for patients with GC.

The sonic hedgehog signaling pathway induces myopic development by activating matrix metalloproteinase (MMP)-2 in Guinea pigs

Purpose

To investigate whether the Sonic hedgehog (Shh) signaling induces myopic development by increasing the expression of matrix metalloproteinase (MMP)-2 in guinea pigs.

Methods

A translucent diffuser was glued onto the right eye to induce form-deprivation myopia (FDM) in 10 guinea pigs. Four guinea pigs were served as a control group. The other 100 guinea pigs were subdivided into 5 groups (20 per group) and received a 10 µl intravitreal injection every 2 days for 4 times. Two groups were injected with 20 or 50 µg/ml Shh amino-terminal peptide (Shh-N) into the right eye and 0.1% bovine serum albumin into the other. FDM was induced in the right eyes of the three cyclopamine-treated groups and both eyes were injected with 50, 100, or 200 µg/ml cyclopamine. Retinoscopic refraction and eye dimensions were assessed on Day 14 of treatment. MMP-2 protein expression was determined in both scleras by western blotting.

Results

Both concentrations of Shh-N stimulated myopic development and axial growth as compared with control eyes. Myopia and axial elongation were significantly greater in the 50 µg/ml than in the 20 µg/ml Shh-N group (P<0.001 and P = 0.0019, respectively). All three doses of cyclopamine significantly attenuated myopic development compared with the FDM group (P<0.0001). Cyclopamine at 100 or 200 µg/ml significantly reduced axial elongation compared with the FDM group (P = 0.044 and P = 0.001, respectively). FDM-induced myopia and axial elongation were significantly greater in the 50 µg/ml than in the 200 µg/ml cyclopamine group (P<0.0001 and P = 0.008, respectively). MMP-2 expression was significantly greater in Shh-N–treated eyes than in the control eyes, and was lower in the cyclopamine plus FDM groups than in the FDM group.

Conclusions

The Shh signaling pathway induces myopic development by activating MMP-2 in guinea pigs.

Daidzein suppresses tumor necrosis factor-α induced migration and invasion by inhibiting hedgehog/Gli1 signaling in human breast cancer cells

In breast cancer, the cytokine tumor necrosis factor-α (TNF-α) induces cell invasion, although the molecular basis of it has not been clearly elucidated. In this study, we investigated the role of daidzein in regulating TNF-α induced cell invasion and the underlying molecular mechanisms. Daidzein inhibited TNF-α induced cellular migration and invasion in estrogen receptor (ER) negative MCF10DCIS.com human breast cancer cells. TNF-α activated Hedgehog (Hh) signaling by enhancing Gli1 nuclear translocation and transcriptional activity, which resulted in increased invasiveness; these effects were blocked by daidzein and the Hh signaling inhibitors, cyclopamine and vismodegib. Moreover, these compounds suppressed TNF-α induced matrix metalloproteinase (MMP)-9 mRNA expression and activity. Taken together, mammary tumor cell invasiveness was stimulated by TNF-α induced activation of Hh signaling; these effects were abrogated by daidzein, which suppressed Gli1 activation, thereby inhibiting migration and invasion.

Additive effects of EGF and IL-1β regulate tumor cell migration and invasion in gastric adenocarcinoma via activation of ERK1/2

Growth and inflammatory factors are associated with poor prognosis in gastric adenocarcinoma (GA); however, the additive effects of growth and inflammatory factors in GA remain unclear. In this study, we investigated the ability of epidermal growth factor (EGF) and interleukin (IL-1β) to activate extracellular signal-regulated kinase (ERK)1/2 in GA cells, and correlated the relationships between their roles with the metastatic potential both in GA cells and GA tissues. The effects of EGF, IL-1β and EGF plus IL-1β in AGS and MKN-45 GA cells were examined using western blotting, Transwell migration and invasion assays, immunocytochemical staining and an activator protein (AP)-1 luciferase reporter gene assay, and was further characterized in GA tissues by immunohistochemistry. The results exhibited that EGF and IL-1β additively activated ERK1/2, increased migration and invasion than either EGF or IL-1β alone in AGS and MKN-45 cells. The mechanisms were involved in upregulating MMP-9 expression through increasing AP-1 transcriptional activity via ERK1/2 pathway; these effects were dose-dependently inhibited by silencing ERK1/2 or using U0126. In vivo data also confirmed that the overexpression of p-ERK1/2 in GA tissues correlated well with the EGF, IL-1β, EGF plus IL-1β, and was associated with metastasis, which was well correlation with the expression of MMP-9 and c-fos (AP-1). The results demonstrate that growth and inflammatory factors play an important role in metastasis of GA by additively activating ERK-1/2 and AP-1, and upregulating MMP-9. As both cytokines contribute to the migration and invasion of GA cells, EGF/IL-1β/ERK1/2 pathways may be key pathways closely associated with GA progression.

Activation of hedgehog signaling pathway in human non-small cell lung cancers

The activation of the hedgehog pathway, which is an important signaling mechanism crucial in embryogenesis, has strong links to carcinogenesis. Aberrant regulation of this pathway can result in the development of tumors. The present study was designed to investigate Hh related protein expression in non-small cell lung cancers. Fifty five non-small cell lung cancers samples were used in the study. By reverse transcription-polymerase chain reaction (RT-PCR), the expression of Shh, Ptch-1, and Gli-1 in tumor and adjacent normal tissues was examined and associated to clinical pathologic features. The expression levels of Shh, Ptch-1, Gli-1 in non-small cell lung cancer tissues were 63.64, 69.09, 43.64 %, respectively, higher than that in the adjacent normal tissues. Survival analysis showed that both Ptch-1 and Gli-1 expression were associated with poor survival (both P <0.05, log-rank test). Shh and Ptch-1 expression were correlated with lymph node metastasis. These results suggest that dysregulation of Hh signaling pathway plays an important role in the development of human NSCLCs. The expression of Ptch-1 and Gli-1 is possibly involved in NSCLCs progression, which may be a useful prognostic indicator of NSCLCs.

Activation of the Akt/mTOR pathway in dentigerous cysts, odontogenic keratocysts, and ameloblastomas

OBJECTIVE

The aim of this study was to investigate the Akt/mTOR pathway in dentigerous cysts (DCs), odontogenic keratocysts (OKCs), and ameloblastomas.

STUDY DESIGN

A total of 90 cases were studied (30 DCs, 30 OKCs, and 30 ameloblastomas). Patient records on age, sex, lesion location, symptoms, and radiographic and histopathologic features were collected. The phosphorylation of components of the Akt/mTOR pathway [p-Akt (Ser473), p-Akt (Thr308), and phosphorylated-ribosomal protein S6 (p-RPS6)] was studied using immunohistochemistry. Correlations with clinical features were analyzed using the Spearman rank test.

RESULTS

Over 90% of OKCs and ameloblastomas and 60% of DCs stained positive for p-Akt (Ser473). Phospho-Akt (Thr308) was positive in 73% of ameloblastomas, 40% of OKCs, and 20% of DCs. Phospho-RPS6 was detected most frequently in OKCs (83%), followed by ameloblastomas (76%) and DCs (53%). No correlations were noted between the immunohistochemical findings and the clinicopathologic parameters.

CONCLUSIONS

The Akt/mTOR pathway is upregulated in DCs, OKCs, and ameloblastomas. This pathway may be involved in the development of these lesions.

Restoration of PPP2CA expression reverses epithelial-to-mesenchymal transition and suppresses prostate tumour growth and metastasis in an orthotopic mouse model

BACKGROUND

Emergence of castration-resistance in prostate cancer (PCa) is invariably associated with aggressive and metastatic disease. Previously, we reported promotion of castration-resistance upon downregulation of PPP2CA (encoding catalytic subunit of protein phosphatase 2A (PP2A), α-isoform); however, its role in PCa growth and metastasis remained undetermined.

METHODS

PPP2CA was overexpressed/silenced in PCa cells by stable transfection. Gene expression was examined by reverse transcription polymerase chain reaction, immunoblot and immunofluorescence analyses, and transcriptional activity measured by luciferase-based promoter-reporter assay. Effect on PCa phenotype was studied in vitro and in orthotopic mouse model, and immunohistochemical/histological analyses performed to assess proliferation/apoptosis and confirm metastatic lesions.

RESULTS

An inverse association of PPP2CA expression was observed with epithelial-to-mesenchymal transition (EMT) and aggressive PCa phenotype. PPP2CA restoration resulted in decreased nuclear accumulation and transcriptional activity of β-catenin/NF-κB, and restitution of their activity abrogated PPP2CA-induced EMT reversal and suppression of PCa invasiveness. Akt mediated PPP2CA loss-induced nuclear accumulation of β-catenin/NF-κB through inactivation of Gsk3-β and IκB-α, respectively. Animal studies revealed a suppressive effect of PPP2CA expression on PCa growth and metastasis.

CONCLUSIONS

Our findings suggest that PPP2CA downregulation serves as a molecular link between gain of castration-resistance and aggressive PCa phenotype, and its restoration could be an effective preventive/therapeutic approach against the advanced disease.

Lymphangiogenesis and lymphatic vessel remodelling in cancer

The generation of new lymphatic vessels through lymphangiogenesis and the remodelling of existing lymphatics are thought to be important steps in cancer metastasis. The past decade has been exciting in terms of research into the molecular and cellular biology of lymphatic vessels in cancer, and it has been shown that the molecular control of tumour lymphangiogenesis has similarities to that of tumour angiogenesis. Nevertheless, there are significant mechanistic differences between these biological processes. We are now developing a greater understanding of the specific roles of distinct lymphatic vessel subtypes in cancer, and this provides opportunities to improve diagnostic and therapeutic approaches that aim to restrict the progression of cancer.

Crosstalk between hedgehog and other signaling pathways as a basis for combination therapies in cancer

The hedgehog (Hh) pathway is aberrantly activated in a number of tumors. In medulloblastoma, basal cell carcinoma, and rhabdomyosarcoma, mutations in Hh pathway genes lead to ligand-independent pathway activation. In many other tumor types, ligand-dependent activation of Hh signaling is potentiated through crosstalk with other critical molecular signaling pathways. Among such pathways, RAS/RAF/MEK/ERK, PI3K/AKT/mTOR, EGFR, and Notch are of particular interest because agents that selectively inhibit these pathways are available and can be readily combined with agents such as vismodegib, sonidegib (LDE225), and BMS-833923, which target smoothened-a key Hh pathway regulator. Numerous preclinical studies have revealed the ways in which Hh intersects with each of these pathways, and combination therapies have resulted in improved antitumor efficacy and survival in animal models. Hh also plays an important role in hematopoiesis and in the maintenance of BCR-ABL-driven leukemic stem cells. Thus, combined inhibition of the Hh pathway and BCR-ABL has emerged as a promising potential therapeutic strategy in chronic myeloid leukemia (CML). A number of clinical trials evaluating combinations of Hh inhibitors with other targeted agents are now underway in CML and a variety of solid tumors. This review highlights these trials and summarizes preclinical evidence of crosstalk between Hh and four other actionable pathways-RAS/RAF/MEK/ERK, PI3K/AKT/mTOR, EGFR, and Notch-as well as the role of Hh in the maintenance of BCR-ABL-driven leukemic stem cells.

Gelatinase B/MMP-9 in Tumour Pathogenesis and Progression

Since its original identification as a leukocyte gelatinase/type V collagenase and tumour type IV collagenase, gelatinase B/matrix metalloproteinase (MMP)-9 is now recognised as playing a central role in many aspects of tumour progression. In this review, we relate current concepts concerning the many ways in which gelatinase B/MMP-9 influences tumour biology. Following a brief outline of the gelatinase B/MMP-9 gene and protein, we analyse the role(s) of gelatinase B/MMP-9 in different phases of the tumorigenic process, and compare the importance of gelatinase B/MMP-9 source in the carcinogenic process. What becomes apparent is the importance of inflammatory cell-derived gelatinase B/MMP-9 in tumour promotion, early progression and triggering of the "angiogenic switch", the integral relationship between inflammatory, stromal and tumour components with respect to gelatinase B/MMP-9 production and activation, and the fundamental role for gelatinase B/MMP-9 in the formation and maintenance of tumour stem cell and metastatic niches. It is also apparent that gelatinase B/MMP-9 plays important tumour suppressing functions, producing endogenous angiogenesis inhibitors, promoting inflammatory anti-tumour activity, and inducing apoptosis. The fundamental roles of gelatinase B/MMP-9 in cancer biology underpins the need for specific therapeutic inhibitors of gelatinase B/MMP-9 function, the use of which must take into account and substitute for tumour-suppressing gelatinase B/MMP-9 activity and also limit inhibition of physiological gelatinase B/MMP-9 function.

MiR-133b is frequently decreased in gastric cancer and its overexpression reduces the metastatic potential of gastric cancer cells

Background

Emerging evidence has shown that microRNAs are involved in gastric cancer development and progression. Here we examine the role of miR-133b in gastric cancer.

Methods

Quantitative real-time PCR analysis was performed in 140 patient gastric cancer tissues and 8 gastric cancer cell lines. The effects of miR-133b in gastric cancer cells metastasis were examined by scratch assay, transwell migration and matrigel invasion. In vivo effects of miR-133b were examined in an intraperitoneal mouse tumor model. Targets of miR-133b were predicted by bioinformatics tools and validated by luciferase reporter analyses, western blot, and quantitative real-time PCR.

Results

MiR-133b was significantly downregulated in 70% (98/140) of gastric cancer patients. Expression of miR-133b was negatively correlated with lymph node metastasis of gastric cancer in patients. Similarly, the expression of miR-133b was significantly lower in seven tested gastric cancer cell lines than in the immortalized non-cancerous GES-1 gastric epithelial cells. Overexpression of miR-133b markedly inhibited metastasis of gastric cancer cells in vitro and in vivo. Moreover, the transcriptional factor Gli1 was identified as a direct target for miR-133b. Level of Gli1 protein but not mRNA was decreased by miR-133b. Activity of luciferase with Gli1 3′-untranslated region was markedly decreased by miR-133b in gastric cancer cells. Gli1 target genes, OPN and Zeb2, were also inhibited by miR133b.

Conclusions

MiR-133b is frequently decreased in gastric cancer. Overexpression of miR-133b inhibits cell metastasis in vitro and in vivo partly by directly suppressing expression of Gli1 protein. These results suggested that miR-133b plays an important role in gastric cancer metastasis.

Breast cancer stem cells transition between epithelial and mesenchymal states reflective of their normal counterparts

Previous studies have suggested that breast cancer stem cells (BCSCs) mediate metastasis, are resistant to radiation and chemotherapy, and contribute to relapse. Although several BCSC markers have been described, it is unclear whether these markers identify the same or independent BCSCs. Here, we show that BCSCs exist in distinct mesenchymal-like (epithelial-mesenchymal transition [EMT]) and epithelial-like (mesenchymal-epithelial transition [MET]) states. Mesenchymal-like BCSCs characterized as CD24⁻CD44⁺ are primarily quiescent and localized at the tumor invasive front, whereas epithelial-like BCSCs express aldehyde dehydrogenase (ALDH), are proliferative, and are located more centrally. The gene-expression profiles of mesenchymal-like and epithelial-like BCSCs are remarkably similar across different molecular subtypes of breast cancer, and resemble those of distinct basal and luminal stem cells found in the normal breast. We propose that the plasticity of BCSCs that allows them to transition between EMT- and MET-like states endows these cells with the capacity for tissue invasion, dissemination, and growth at metastatic sites.

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BCSCs exist in EMT and MET states with distinct marker and gene-expression profiles

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CSCs from different subtypes of breast cancer express common EMT/MET genes

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EMT and MET BCSC profiles resemble normal mammary basal and luminal stem cells

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BCSCs display plasticity that enables them to transition between EMT and MET states

Hypoxia and lymphangiogenesis in tumor microenvironment and metastasis

Hypoxia and lymphangiogenesis are closely related processes that play a pivotal role in tumor invasion and metastasis. Intratumoral hypoxia is exacerbated as a result of oxygen consumption by rapidly proliferating tumor cells, insufficient blood supply and poor lymph drainage. Hypoxia induces functional responses in lymphatic endothelial cells (LECs), including cell proliferation and migration. Multiple factors (e.g., ET-1, AP-1, C/EBP-δ, EGR-1, NF-κB, and MIF) are involved in the events of hypoxia-induced lymphangiogenesis. Among them, HIF-1α is known to be the master regulator of cellular oxygen homeostasis, mediating transcriptional activation of lymphangiogenesis via regulation of signaling cascades like VEGF-A/-C/-D, TGF-β and Prox-1 in experimental and human tumors. Although the underlying molecular mechanisms remain incompletely elucidated, the investigation of lymphangiogenesis in hypoxic conditions may provide insight into potential therapeutic targets for lymphatic metastasis.

Rubus idaeus L Inhibits Invasion Potential of Human A549 Lung Cancer Cells by Suppression Epithelial-to-Mesenchymal Transition and Akt Pathway In Vitro and Reduces Tumor Growth In Vivo

The metastasis of lung cancer is the most prevalent cause of patient death. Various treatment strategies have targeted the prevention of the occurrence of metastasis. The epithelial-mesenchymal transition (EMT) in lung cancer cells is considered a prerequisite to acquire the invasive/migratory phenotype and to subsequently achieve metastasis. However, the effects ofRubus idaeuson cancer invasion and the EMT of the human lung carcinoma remain unclear. In this article, we test the hypothesis thatR idaeusethyl acetate (RIAE) possesses an antimetastatic effect and reverses the EMT potential of human lung A549 cells. We extract the raspberryR idaeuswith methanol (RIME), chloroform (RICE), ethyl acetate (RIAE),n-butanol (RIBE), and water (RIWE). The RIAE treatment obviously inhibits the invasive (P< .001), motility (P< .001), spreading, and migratory potential (P< .001) of highly metastatic human lung cancer A549 cells. The zymography and promoter luciferase analysis reveals that RIAE decreases the proteinase and transcription activities of MMP-2 and u-PA. Molecular analyses show that RIAE increases the E-cadherin level that is mainly localized at the cellular membrane. This result was also verified through confocal analyses. RIAE also induces the upregulation of an epithelial marker, such as α-catenin, and decreases mesenchymal markers, such as snail-1 and N-cadherin, that promote cell invasion and metastasis. RIAE inhibits MMP-2 and u-PA by attenuating the NF-κB and p-Akt expression. The inhibition of RIAE on the growth of A549 cells in vivo was also verified using a cancer cell xenograft nude mice model. Our results show the anti-invasive/antitumor effects of RIAE and associated mechanisms, which suggest that RIAE should be further tested in clinically relevant models to exploit its potential benefits against metastatic lung cancer cells.

Derivation of lung mesenchymal lineages from the fetal mesothelium requires hedgehog signaling for mesothelial cell entry

Recent studies have shown that mesothelial progenitors contribute to mesenchymal lineages of developing organs. To what extent the overlying mesothelium contributes to lung development remains unknown. To rigorously address this question, we employed Wt1(CreERT2/+) mice for high-fidelity lineage tracing after confirming that Cre recombinase was mesothelial specific and faithfully recapitulated endogenous Wilms' tumor 1 (Wt1) gene expression. We visualized WT1(+) mesothelial cell entry into the lung by live imaging and identified their progenies in subpopulations of bronchial smooth muscle cells, vascular smooth muscle cells and desmin(+) fibroblasts by lineage tagging. Derivation of these lineages was only observed with Cre recombinase activation during early lung development. Using loss-of-function assays in organ cultures, and targeted mesothelial-restricted hedgehog loss-of-function mice, we demonstrated that mesothelial cell movement into the lung requires the direct action of hedgehog signaling. By contrast, hedgehog signaling was not required for fetal mesothelial heart entry. These findings further support a paradigm wherein the mesothelium is a source of progenitors for mesenchymal lineages during organogenesis and indicate that signals controlling mesothelial cell entry are organ specific.

Thrombospondin-1/CD36 pathway contributes to bone marrow-derived angiogenic cell dysfunction in type 1 diabetes via Sonic hedgehog pathway suppression

Refractory wounds in diabetic patients present a significant clinical problem. Sonic hedgehog (SHH), a morphogenic protein central to wound repair, is deficient in diabetes. Regulation of SHH in wound healing is poorly understood. We hypothesize that thrombospondin-1 (TSP-1), through its receptor CD36, contributes to the SHH signaling defect in bone marrow-derived angiogenic cells (BMACs) in type 1 diabetic mice. Isolated BMACs from TSP-1-knockout mice demonstrated improved tube formation, migration, and adhesion in parallel with active SHH signaling. BMACs from STZ-induced type 1 diabetic mice showed significantly impaired Matrigel tube formation (n = 5; P < 0.05 vs. control), which was rescued by TSP-1 depletion (n = 5; P < 0.05 STZ-TSP-1(-/-) vs. STZ-WT) or exogenous SHH (20 mg/l, 24 h, n = 4; P < 0.05 vs. STZ-control). The expression of CD36 was elevated in BMACs from STZ mice (n = 4; P < 0.05). SHH signaling was significantly higher in BMACs from TSP-1(-/-) mice and TSP-1 receptor CD36-knockout mice (n = 6; P < 0.05 vs. WT) but not CD47-knockout mice (n = 3; P > 0.05 vs. WT). The impairment of recombinant human TSP-1 (2.2 nM, 24 h) on BMAC Matrigel tube formation was delayed significantly by CD36 deletion (n = 5; P < 0.05). CD36(-/-) BMACs demonstrated better tube formation under both normal and diabetic conditions with active SHH signaling (n = 4; P < 0.05 vs. WT BMACs). In conclusion, The TSP-1/CD36 pathway contributes to the SHH signaling defect, resulting in BMAC dysfunction in type 1 diabetic mice.

Hedgehog signal inhibitors suppress the invasion of human rhabdomyosarcoma cells

PURPOSE

In the treatment of rhabdomyosarcoma (RMS), invasion and metastasis remain the most critical determinants of resectability and survival. The objective of this study was to determine whether Hedgehog (Hh) signaling plays a role in the invasion of RMS.

METHODS

Two kinds of specific Hh signaling inhibitors, cyclopamine and forskolin, were used to suppress activated Hh signals in three RMS cell lines. The effects of the Hh signaling inhibitors on tumor cell invasion and motility were investigated using Matrigel invasion assays and wound closure assays, respectively.

RESULTS

The number of invaded cells counted in six random microscopic fields in the Matrigel chambers was significantly decreased by both cyclopamine and forskolin in every RMS cell line. Furthermore, the wound closure assays revealed that a blockade of the Hh signaling pathway by the Hh inhibitors strongly impairs RMS cell motility, as visualized by the delayed closure of the gaps generated in the cultured cell monolayers of the three RMS cell lines.

CONCLUSIONS

Both the invasive capacity and motility of RMS cells are significantly suppressed by Hh signaling inhibitors, demonstrating that the Hh pathway plays an important role in the invasion of RMS. Hh inhibitors may provide a new paradigm for the treatment of RMS.

Rubus idaeus L. reverses epithelial-to-mesenchymal transition and suppresses cell invasion and protease activities by targeting ERK1/2 and FAK pathways in human lung cancer cells

Epithelial to mesenchymal transition (EMT) has been considered essential for cancer metastasis, a multistep complicated process including local invasion, intravasation, extravasation, and proliferation at distant sites. Herein we provided molecular evidence associated with the antimetastatic effect of Rubus idaeus L. extracts (RIE) by showing a nearly complete inhibition on the invasion (p<0.001) of highly metastatic A549 cells via reduced activities of matrix metalloproteinase-2 (MMP-2) and urokinasetype plasminogen activator (u-PA). We performed Western blot to find that RIE could induce up-regulation of epithelial marker such as E-cadherin and α-catenin and inhibit the mesenchymal markers such as N-cadherin, fibronectin, snail-1, and vimentin. Selective snail-1 inhibition by snail-1-specific-siRNA also showed increased E-cadherin expression in A549 cells suggesting a possible involvement of snail-1 inhibition in RIE-caused increase in E-cadherin level. RIE also inhibited p-FAK, p-paxillin and AP-1 by Western blot analysis, indicating the anti-EMT effect of RIE in human lung carcinoma. Importantly, an in vivo BALB/c nude mice xenograft model showed that RIE treatment reduced tumor growth by oral gavage, and RIE represent promising candidates for future phytochemical-based mechanistic pathway-targeted cancer prevention strategies.

Significance and prognostic value of Gli-1 and Snail/E-cadherin expression in progressive gastric cancer

Abnormal activation of the hedgehog (Hh) signaling pathway has been found to be involved in the occurrence, invasion, and metastasis of cancers. Epithelial-mesenchymal transition (EMT) also plays an important role in the invasion and metastasis of cancers. However, the significance of the Hh signaling pathway and EMT in the invasion and metastasis of gastric cancer is still unclear. This study aimed to investigate the significance and prognostic value of the Hh signaling pathway and EMT in progressive gastric cancer. Immunohistochemistry was performed to detect the expression of the Hh-induced transcriptional factor Gli-1 and the EMT-related molecules Snail and E-cadherin in 121 patients with progressive gastric cancer. Histological type, depth of invasion, lymph node metastasis, and pTNM stage were also recorded. In progressive gastric cancer, Gli-1 expression increased markedly, and was closely associated with increased Snail expression and decreased E-cadherin expression. Diffuse type cancer, lymph node metastasis, and abnormal expression of E-cadherin were independent factors influencing the prognosis of patients with progressive gastric cancer. These findings suggest that abnormal activation of the Hh signaling pathway is closely related to the presence of EMT and is an important factor influencing the prognosis of patients with diffuse progressive gastric cancer.

Suppression of growth and migration by blocking the Hedgehog signaling pathway in gastric cancer cells

PURPOSE

Previous studies have indicated that Hedgehog signaling is essential for gastric cancer development, but its precise role is still unclear. The aim of this study was to clarify the role of Hedgehog signaling in gastric cancer development.

METHODS

The expression of key Hedgehog signaling components in clinical samples of sequential gastric cancer stages was assessed by immunohistochemistry. The roles and regulatory mechanisms of Hedgehog signaling in human gastric cancer cells and normal gastric epithelial cells were investigated using multiple cell biological approaches and cDNA microarray analyses.

RESULTS

Hedgehog signaling was found to be abnormally activated in a ligand-independent manner during gastric cancer development. Gli1 over-expression and reduced SuFu expression were found to be typical events in gastric cancer tissues. Gli1 over-expression was found to correlate with a poorly differentiated histology, advanced clinical stage, membrane serosa infiltration and lymph node metastasis in patients with gastric cancer. Data obtained from multiple cell biological assays showed that human gastric cancer cells require active Hedgehog signaling for survival, proliferation, migration and colony formation. N-Shh treatment significantly enhanced the migration, invasion and colony formation of gastric cancer cells. Moreover, the results of cDNA microarray analyses indicated that after treatment with cyclopamine or GANT61 (inhibitors of Hedgehog signaling), differentially expressed genes in gastric cancer cells were enriched in the apoptosis and MAPK pathways. Inhibitors of the Hedgehog pathway were found to suppress gastric cancer cell growth via apoptosis induction.

CONCLUSIONS

Our findings indicate a vital role of the activated Hedgehog signaling pathway in promoting gastric initiation and progression. The Hedgehog signaling pathway may serve as a target for gastric cancer therapy.

Norcantharidin, derivative of cantharidin, for cancer stem cells

Cancer stem cells (CSCs) existing in human cancers have been demonstrated to be a major cause of cancer treatment resistance, invasion, metastasis, and relapse. Self-renewal pathways, Wnt/β-catenin, Sonic hedgehog (Shh), and the Notch signaling pathway play critical roles in developing CSCs and lead to angiogenesis, migration, invasion, and metastasis. Multidrug resistance (MDR) is an unfavorable factor causing the failure of treatments against cancer cells. The most important and thoroughly studied mechanism involved in MDR is the active efflux of chemotherapeutic agents through membrane drug transporters. There is growing evidence that Norcantharidin (NCTD), a water-soluble synthetic small molecule derivative of naturally occurring cantharidin from the medicinal insect blister beetle (Mylabris phalerata Pallas), is capable of chemoprevention and tumor inhibition. We summarize investigations into the modulation of self-renewal pathways and MDR in CSCs by NCTD. This review may aid in further investigation of using NCTD to develop more effective strategies for cancer treatment to reduce resistance and recurrence.

Laser microdissection and two-dimensional difference gel electrophoresis reveal the role of a novel macrophage-capping protein in lymph node metastasis in gastric cancer

To reveal the proteomic background of lymph node metastasis (LNM) in gastric cancer, we performed a proteomic study of tumor and matched nontumor tissues obtained from surgically resected specimens of 22 patients with or without LNM. Using laser microdissection, we recovered specific populations of tumor and nontumor cells. We used two-dimensional difference gel electrophoresis with a large format electrophoresis apparatus to obtain protein expression profiles consisting of 3228 protein spots, and we classified them according to their expression pattern. We found that macrophage-capping protein (CapG) was up-regulated in the tumor tissues of patients with LNM, whereas it showed an equivalent expression level between nontumor and tumor tissues of patients without LNM. It was reported that CapG associated with invasion and metastasis in various malignancies. However, CapG was not investigated in gastric cancer until our study. Western blotting of the laser microdissected tissue samples confirmed up-regulation of CapG in the tumor tissues of patients with LNM. Functional assays demonstrated that CapG promoted tumor cell invasion, but not cell proliferation. The association between CapG expression and LNM is a novel finding in gastric cancer. Further investigation for a prognostic utility of CapG may lead to a risk stratification therapy for gastric cancer.

Gli1 mediates lung cancer cell proliferation and Sonic Hedgehog-dependent mesenchymal cell activation

Non-Small-Cell-Lung-Cancer (NSCLC) represents approximately 85% of all lung cancers and remains poorly understood. While signaling pathways operative during organ development, including Sonic Hedgehog (Shh) and associated Gli transcription factors (Gli1-3), have recently been found to be reactivated in NSCLC, their functional role remains unclear. Here, we hypothesized that Shh/Gli1-3 could mediate NSCLC autonomous proliferation and epithelial/stromal signaling in the tumoral tissue. In this context, we have investigated the activity of Shh/Gli1-3 signaling in NSCLC in both, cancer and stromal cells. We report here that inhibition of Shh signaling induces a significant decrease in the proliferation of NSCLC cells. This effect is mediated by Gli1 and Gli2, but not Gli3, through regulation of cyclin D1 and cyclin D2 expression. While exogenous Shh was unable to induce signaling in either A549 lung adenocarcinoma or H520 lung squamous carcinoma cells, both cells were found to secrete Shh ligand, which induced fibroblast proliferation, survival, migration, invasion, and collagen synthesis. Furthermore, Shh secreted by NSCLC mediates the production of proangiogenic and metastatic factors in lung fibroblasts. Our results thus provide evidence that Shh plays an important role in mediating epithelial/mesenchymal crosstalk in NSCLC. While autonomous Gli activity controls NSCLC proliferation, increased Shh expression by NSCLC is associated with fibroblast activation in tumor-associated stroma. Our study highlights the relevance of studying stromal-associated cells in the context of NSCLC regarding new prognosis and therapeutic options.

NVP-LDE-225 (Erismodegib) inhibits epithelial-mesenchymal transition and human prostate cancer stem cell growth in NOD/SCID IL2Rγ null mice by regulating Bmi-1 and microRNA-128

Prostate cancer stem cells (CSCs) are defined by their extensive self-renewal, differentiation and tumor initiation properties. It is now clear that CSCs are involved in tumor growth and recurrence, and resistance to conventional treatments. The sonic hedgehog (Shh) pathway has a crucial role in stemness and tumorigenesis. Thus, the strategy that suppresses stemness and consequently tumorigenic potential of CSCs could be considered for the management of prostate cancer. The objectives of this study were to examine the molecular mechanisms, by which NVP-LDE-225/Erismodegib (smoothened inhibitor) regulates stem cell characteristics and tumor growth in prostate cancer. The effects of NVP-LDE-225 on CSC's viability, sphere formation, apoptosis, epithelial-mesenchymal transition (EMT) and tumor growth in NOD/SCID IL2Rγ null mice were examined. NVP-LDE-225 inhibited cell viability and spheroid formation, and induced apoptosis by activation of caspase-3 and cleavage of poly-ADP ribose polymerase (PARP). NVP-LDE-225 induced expression of Bax and Bak, and inhibited the expression of Bcl-2, Bcl-XL, XIAP, cIAP1, cIAP2 and survivin. NVP-LDE-225 inhibited Gli transcriptional activity, Gli-DNA interaction and the expression of Gli1, Gli2, Patched1 and Patched-2 in prostate CSCs. Interestingly, NVP-LDE-225 induced PDCD4 and apoptosis and inhibited cell viability by suppressing miR-21. Furthermore, NVP-LDE-225 inhibited pluripotency-maintaining factors Nanog, Oct-4, c-Myc and Sox-2. The inhibition of Bmi-1 by NVP-LDE-225 was regulated by upregulation of miR-128. NVP-LDE-225 suppressed EMT by upregulating E-cadherin and inhibiting N-cadherin, Snail, Slug and Zeb1 by regulating the miR-200 family. Finally, NVP-LDE-225 inhibited CSC tumor growth, which was associated with the suppression of Gli1, Gli2, Patched-1, Patched-2, Cyclin D1, Bmi-1 and PCNA and cleavage of caspase-3 and PARP in tumor tissues derived from NOD/SCID IL2Rγ null mice. Overall, our findings suggest that inhibition of the Shh signaling pathway could therefore be a novel therapeutic option in treating prostate cancer.