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

GLI3 knockdown decreases stemness, cell proliferation and invasion in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is an extremely aggressive disease associated with a poor prognosis. Previous studies have established that cancer stem cells (CSCs) actively participate in OSCC development, progression and resistance to conventional treatments. Furthermore, CSCs frequently exhibit a deregulated expression of normal stem cell signalling pathways, thereby acquiring their distinctive abilities, of which self-renewal is an example. In this study, we examined the effects of GLI3 knockdown in OSCC, as well as the differentially expressed genes in CSC-like cells (CSCLCs) expressing high (CD44^high) or low (CD44^low) levels of CD44. The prognostic value of GLI3 in OSCC was also evaluated. The OSCC cell lines were sorted based on CD44 expression; gene expression was evaluated using a PCR array. Following this, we examined the effects of GLI3 knockdown on CD44 and ESA expression, colony and sphere formation capability, stem-related gene expression, proliferation and invasion. The overexpression of genes related to the Notch, transforming growth factor (TGF)β, FGF, Hedgehog, Wnt and pluripotency maintenance pathways was observed in the CD44^high cells. GLI3 knockdown was associated with a significant decrease in different CSCLC fractions, spheres and colonies in addition to the downregulation of the CD44, Octamer-binding transcription factor 4 (OCT4; also known as POU5F1) and BMI1 genes. This downregulation was accompanied by an increase in the expression of the Involucrin (IVL) and S100A9 genes. Cellular proliferation and invasion were inhibited following GLI3 knockdown. In OSCC samples, a high GLI3 expression was associated with tumour size but not with prognosis. On the whole, the findings of this study demonstrate for the first time, at least to the best of our knowledge, that GLI3 contributes to OSCC stemness and malignant behaviour. These findings suggest the potential for the development of novel therapies, either in isolation or in combination with other drugs, based on CSCs in OSCC.

Inhibition of sonic hedgehog and PI3K/Akt/mTOR pathways cooperate in suppressing survival, self-renewal and tumorigenic potential of glioblastoma-initiating cells

Since PI3K/Akt/mTOR and sonic hedgehog (SHH) signaling pathways are highly activated in glioblastoma-initiating cells (GICs), we examined the effects of inhibiting these pathways on GIC characteristics and tumor growth in mice. NVP-LDE-225 (inhibitor of Smoothened) inhibited the expression of Gli1, Gli2, Smoothened, Patched1, and Patched2, and induced the expression of SuFu, whereas NVP-BEZ-235 (dual inhibitor of PI3K and mTOR) inhibited the expression of p-PI3K, p-Akt, p-mTOR, and p-p70S6K. NVP-LDE-225 co-operated with NVP-BEZ-235 in inhibiting the self-renewal capacity of GICs, expression of pluripotency maintaining factors (Nanog, c-Myc, Oct4, and Sox2), Musashi1, cyclin D1, and Bcl-2, and transcription and expression of Gli, and in inducing the expression of cleaved caspase-3, cleaved PARP and Bim. Additionally, NVP-LDE-225 co-operated with NVP-BEZ-235 in inhibiting epithelial-mesenchymal transition. Finally, the combination of NVP-LDE-225 and NVP-BEZ-235 was superior in inhibiting tumor growth, regulating the expression of pluripotency promoting factors, stem cell markers, cell cycle, and cell proliferation, and modulating EMT compared to single agent alone. In conclusion, the combined inhibition of PI3K/Akt/mTOR and SHH pathways was superior to single pathway inhibition in suppressing glioblastoma growth by targeting GICs.

Polymorphism of MMP-9 gene is not associated with the risk of urinary cancers: Evidence from an updated meta-analysis

OBJECTIVE

Matrix metalloproteinases 9 (MMP-9) is a zinc-dependent gelatinase, which could decrease the expression of extracellular matrix proteins and influence the metastatic behavior of tumors. In order to draw a comprehensive and precise result about the relationship of MMP-9 and urinary cancers, we presented the current meta-analysis.

METHODS

We searched the PubMed, EMbase, Web of Science, CBM, CNKI and Wanfang databases, the cited references were also manually searched again, covering all the papers published until August 2018. Quality assessment was conducted using the Newcastle-Ottawa Scale. All the meta-analysis was conducted with Stata version 12.0 software to assess the strength of the association. Linkage disequilibrium (LD) analyses of gene polymorphisms and in-silico analysis of MMP-9 expression were also conducted to illustrate the relationship.

RESULTS

17 case-control studies comprise of more than 6154 cases and 6330 controls were enrolled and analyzed. After analyzed, we found that there is no significant association between rs3918241, rs2250889, rs17576 and rs17577 of MMP-9 and urinary cancers. LD analysis uncovered a significant LD between rs3918241 and rs17577 in CEU, CHB&CHS, ESN, and JPT populations (CEU: r² = 1.0; CHB&CHS: r² = 1.0; ESN: r² = 0.74; JPT: r² = 0.77), as well as a remarkable LD between rs17576 and rs2250889 in CHB&CHS and JPT populations (CHB&CHS: r² = 0.81; JPT: r² = 0.82). Furthermore, in-silico results indicated that the expression of MMP-9 in cancer tissue was higher than that in normal tissue in prostate cancer (Transcripts Per Kilobase Million (TPM) = 7.14 vs. 1.36, P < 0.001), bladder cancer (TPM = 14.2 vs. 2.47, P < 0.001), kidney renal clear cell carcinoma (TPM = 7.43 vs. 1.61, P < 0.001), kidney renal papillary cell carcinoma (TPM = 5.52 vs. 1.74, P = 0.002).

CONCLUSIONS

rs3918241, rs2250889, rs17576 and rs17577 polymorphisms of MMP-9 are not associated with altered risk of urinary cancer. More studies with large sample size focused on the combined effect of two or more polymorphisms of MMP-9 are necessary in the future.

The influence of aberrant expression of GLI1/p-S6K on colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers worldwide. Recent studies have reported that PI3K/AKT/mTOR pathway regulated the GLI1 expression level via SMO-independent pathway in a variety of tumor types. We detected the expression level of GLI1/p-S6K in CRC tissues. We found the expression of GLI1/p-S6K was apparently close with lymph node metastasis and TNM stage and patients with positive GLI1/p-S6K expression had shorter survival time and patients with both GLI1 and p-S6K positive expression had an even worse overall survival than those with single positive expression. Moreover, GLI1 and p-S6K expression was considered to be independent prognostic factors in CRC patient and the positive co-expression of GLI1/p-S6K had greater influence than single expression positive on the prognosis of postoperative patients with tumor size≥5 cm, well differentiation, positive lymph node metastasis, venous invasion, neural invasion and TNM III-IV. Meanwhile, the GLI1/p-S6K expression had impact on more clinicopathologic features in colon-side carcinoma than in rectum-side carcinoma and the mTOR/S6K/GLI1 axis played an important role in CRC especially in advanced stage. Hence, further studies are underway to explore the molecular mechanism between GLI1 and p-S6K in CRC, and in addition, it offers novel facilities for molecular targeting therapy for CRC.

CYP24A1 depletion facilitates the antitumor effect of vitamin D3 on thyroid cancer cells

It has been demonstrated that 25-hydroxyvitamin-D3-24-hydroxylase (CYP24A1) is a key enzyme that neutralizes vitamin D activity, which may have an anti-tumor effect. Therefore, the aim of the current study was to explore the effect of the active metabolite of vitamin D, 1,25-dihydroxyvitamin D (1,25-D3) on thyroid cancer cells following the downregulation of CYP24A1. A Cell Counting Kit-8 assay identified that CYP24A1 knockdown enhanced the anti-proliferative effects of 1,25-D3 on thyroid cancer cells. Furthermore, the results of the scratch wound and Transwell assays indicated that CYP24A1 knockdown enhanced the inhibitory effect of 1,25-D3 on cell migration. The results from reverse transcription-quantitative polymerase chain reaction and western blot analysis indicated that treatment with 1,25-D3 and CYP24A1 knockdown synergistically enhanced the expression of the epithelial-related gene E-cadherin and decreased the expression of the mesenchymal-related genes N-cadherin and vimentin. Following CYP24A1 knockdown and treatment with 1,25-D3, the expression of matrix metalloproteinase 2 and metalloproteinase inhibitor 1 were significantly decreased and increased, respectively, compared with the group that underwent treatment with 25-D3 alone. Furthermore, protein kinase B (Akt) and β-catenin activity was significantly decreased by this synergetic effect compared with the group that underwent treatment with 1,25-D3 alone. The results of the current study suggest that CYP24A1 knockdown contributes to the anti-tumor effect of 1,25-D3 and that this effect may be due to deactivation of the Akt and β-catenin signaling pathways. Therefore, CYP24A1 knockdown and 1,25-D3 treatment may be used synergistically as a novel therapeutic strategy to treat patients with thyroid cancer.

Modulation of sonic hedgehog-induced mouse embryonic stem cell behaviours through E-cadherin expression and integrin β1-dependent F-actin formation

BACKGROUND AND PURPOSE

The sonic hedgehog pathway (Shh) plays a central role in maintaining stem cell function and behaviour in various processes related to self-renewal and tissue regeneration. However, the therapeutic effect of Shh on mouse embryonic stem cells (mESCs) has not yet been clearly elucidated. Thus, we investigated the effect of Shh on the regulation of mESC behaviour as well as the effect of Shh-pretreated mESCs in skin wound healing.

EXPERIMENTAL APPROACH

The underlying mechanisms of Shh signalling pathway in growth and motility of mESCs were investigated using Western blot analysis, a cell proliferation assay and cell migration assay. In addition, the effect of Shh-pretreated mESCs in skin wound healing was determined using a mouse excisional wound splinting model.

KEY RESULTS

Shh disrupted the adherens junction through proteolysis by activating MMPs. In addition, the release of β-catenin from adherens junctions mediated by Shh led to cell cycle-dependent mESC proliferation. Shh-mediated Gli1 expression led to integrin β1 up-regulation, followed by FAK and Src phosphorylation. Furthermore, among the Rho-GTPases, Rac1 and Cdc42 were activated in a Shh-dependent manner while F-actin expression was suppressed by Rac1 and Cdc42 siRNA transfection. Consistent with the in vitro results, the skin wound healing assay revealed that Shh-treated mESCs increased angiogenesis and skin wound repair compared to that in Shh-treated mESCs transfected with integrin β1 siRNA in vivo.

CONCLUSIONS AND IMPLICATIONS

Our results imply that Shh induces adherens junction disruption and integrin β1-dependent F-actin formation by a mechanism involving FAK/Src and Rac1/Cdc42 signalling pathways in mESCs.

Hedgehog signalling in the tumourigenesis and metastasis of osteosarcoma, and its potential value in the clinical therapy of osteosarcoma

The Hedgehog (Hh) signalling pathway is involved in cell differentiation, growth and tissue polarity. This pathway is also involved in the progression and invasion of various human cancers. Osteosarcoma, a subtype of bone cancer, is commonly seen in children and adolescents. Typically, pulmonary osteosarcoma metastases are especially difficult to control. In the present paper, we summarise recent studies on the regulation of osteosarcoma progression and metastasis by downregulating Hh signalling. We also summarise the crosstalk between the Hh pathway and other cancer-related pathways in the tumourigenesis of various cancers. We further summarise and highlight the therapeutic value of potential inhibitors of Hh signalling in the clinical therapy of human cancers.

Molecular alterations of cancer cell and tumour microenvironment in metastatic gastric cancer

The term metastasis is widely used to describe the endpoint of the process by which tumour cells spread from the primary location to an anatomically distant site. Achieving successful dissemination is dependent not only on the molecular alterations of the cancer cells themselves, but also on the microenvironment through which they encounter. Here, we reviewed the molecular alterations of metastatic gastric cancer (GC) as it reflects a large proportion of GC patients currently seen in clinic. We hope that further exploration and understanding of the multistep metastatic cascade will yield novel therapeutic targets that will lead to better patient outcomes.

Small interfering RNA-mediated knockdown of fatty acid synthase attenuates the proliferation and metastasis of human gastric cancer cells via the mTOR/Gli1 signaling pathway

Fatty acid synthase (FASN), the main enzyme involved in de novo lipogenesis, is overexpressed in several types of tumor tissues. In addition, it is associated with tumor cell proliferation, metastasis, epithelial-mesenchymal transition (EMT) and a poor prognosis. However, the precise functions and internal mechanisms of FASN with regard to the proliferation, metastasis and EMT in gastric cancer (GC) cells remain elusive. The present study investigated FASN protein expression in 18 randomly selected pairs of GC tumors and matched normal tissues by western blot analysis. FASN-specific small interfering RNA (siRNA) was then transfected into SGC-7901 cells to examine the effect of FASN on proliferation and migration in vitro. Western blotting was used to detect the protein expression of FASN, EMT-related markers and key signaling molecules of the mechanistic target of rapamycin/zinc finger protein GLI1 (mTOR/Gli1) pathway. Reverse transcription-quantitative polymerase chain reaction was conducted to detect the mRNA expression of FASN and EMT-related markers. The FASN level was higher in the GC tissues compared with that in the surrounding normal tissues. Knockdown of FASN suppressed GC cell proliferation and metastasis in vitro. The silencing of FASN expression using siRNA reversed EMT at the protein and mRNA levels and decreased the expression of Gli1 via regulation of AMP-activated protein kinase/mTOR and protein kinase B/mTOR signaling in GC cells. Inhibition of FASN suppresses GC proliferation and metastasis through targeting of the mTOR/Gli1 signaling pathway, indicating that it may serve as a potential target for the treatment of GC.

Tumor-Associated Macrophages Derived TGF-β‒Induced Epithelial to Mesenchymal Transition in Colorectal Cancer Cells through Smad2,3-4/Snail Signaling Pathway

Purpose

We investigated the role of tumor-associated macrophages (TAMs) on the epithelial to mesenchymal transition (EMT) of colorectal cancer cells and determined the potential mechanism involved in the metastatic process.

Materials and Methods

In this study, flow cytometry was used to detect the expression of target proteins. We used transwell assay to evaluate the migration of cancer cells under specific conditions. Using real-time polymerase chain reaction, we examined the expressions of cytokines and EMT-related markers in mRNA level. Animal assay was performed for analysis in vivo and hematoxylin and eosin was used to visualize the effect of TAMs on tumor metastasis. We also used immunohistochemistry and Western blotting to detect the expression of target proteins.

Results

Here, we observed enrichment of TAMs in colorectal tumor tissues, resulting in high metastasis in clinical therapy. Moreover, those TAMs could facilitate the EMT progression of colorectal cancer cells, which is induced by the transforming growth factor-β (TGF-β) derived from TAMs, leading to the invasion and migration of cancer cells.

Conclusion

Our results demonstrated that TAMs contributed the EMT progression through a TGF-β/Smad2,3-4/Snail signaling pathway, and disrupting this pathway with TGF-β receptor inhibitor could suppress metastasis, readjusting our focus to the connection of TAMs and cancer metastasis.

Targeting GLI Transcription Factors in Cancer

Aberrant activation of hedgehog (Hh) signaling has been observed in a wide variety of tumors and accounts for more than 25% of human cancer deaths. Inhibitors targeting the Hh signal transducer Smoothened (SMO) are widely used and display a good initial efficacy in patients suffering from basal cell carcinoma (BCC); however, a large number of patients relapse. Though SMO mutations may explain acquired therapy resistance, a growing body of evidence suggests that the non-canonical, SMO-independent activation of the Hh pathway in BCC patients can also account for this adverse effect. In this review, we highlight the importance of glioma-associated oncogene (GLI) transcription factors (the main downstream effectors of the canonical and the non-canonical Hh cascade) and their putative role in the regulation of multiple oncogenic signaling pathways. Moreover, we discuss the contribution of the Hh signaling to malignant transformation and propose GLIs as central hubs in tumor signaling networks and thus attractive molecular targets in anti-cancer therapies.

A hydrophobic residue in the TALE homeodomain of PBX1 promotes epithelial-to-mesenchymal transition of gastric carcinoma

Pre-B-cell leukemia homeobox 1 (PBX1) was originally identified as a proto-oncogene in human leukemia. Although this protein has been shown to contribute to cellular development and tumorigenesis, the role of PBX1 in gastric carcinoma (GC) remains unclear. In this study, we observed increased expression of PBX1 in GC tissues compared with adjacent normal tissues. This increase in PBX1 expression levels negatively correlated with HOXB9 mRNA expression and was also associated with malignancy and metastasis. PBX1 promoted proliferation and metastasis of GC cells both in vitro and in vivo. These phenomena were also accompanied by epithelial-to-mesenchymal transition (EMT). Additionally, we observed that PBX1 promotes the expression of tumor growth and angiogenic factors. A structural model of the PBX1-HOX complex revealed that hydrophobic binding between PBX1 and the hexapeptide motif might be required for EMT induction. This analysis also demonstrated that the Phe²⁵² residue in the first helix of the TALE homeodomain is involved in the latter hydrophobic binding reaction. In vitro data from PBX1 mutants suggest that PBX1 cannot promote tumorigenesis of GC cells via EMT induction when Phe²⁵² residues lose hydrophobicity. It is likely that the presence of this residue is essential in facilitating hydrophobic binding with the hexapeptide motif. These findings suggest that PBX1 may be a potential target for GC treatment and this study provides a platform to elucidate the molecular mechanisms that underpin the role of PBX1 in GC tumorigenesis.

Dehydroeffusol inhibits viability and epithelial-mesenchymal transition through the Hedgehog and Akt/mTOR signaling pathways in neuroblastoma cells

Neuroblastoma (NB) is the most predominant extracranial solid tumor of infancy in the world. However, current chemotherapy has limited efficacy for more advanced stages of NB due to acquired chemoresistance or acute toxicity in NB patients. Therefore, effective novel anti-NB drugs are desperately needed. The present study aimed to investigate the effects of dehydroeffusol (DHE), a phenanthrene isolated from J. effuses, on NB cells and its underlying mechanism. The results showed that DHE treatment effectively inhibited NB cell viability in a dose-dependent manner. Moreover, DHE treatment suppressed the epithelial-mesenchymal transition (EMT) process in NB cells by promoting the expression of E-cadherin (E-cad) and restraining the expressions of N-cadherin (N-cad) and vimentin. Also, the invasive capacity and expression of MMP-2 and MMP-9 in NB cells were inhibited by DHE. Furthermore, DHE suppressed the hedgehog (Hh) and the protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathways in NB cells. In conclusion, DHE effectively inhibited the viability and EMT through inactivating the Hh and the Akt/mTOR signaling pathways in NB cells, providing a novel evidence that DHE may be a potential anti-NB drug candidate.

The inhibition of heme oxygenase-1 enhances the chemosensitivity and suppresses the proliferation of pancreatic cancer cells through the SHH signaling pathway

Pancreatic cancer (PC) is a type of cancer associated with a high fatality rate due to a poor prognosis and resistance to treatment. Heme oxygenase-1 (HO-1) is significantly overexpressed in a number of types of cancer and seems to play an important role in cancer progression. In this study, we examined the potential effects of HO-1 on PC cell proliferation and sensivity to gemcitabine (Gem). Furthermore, the role of the sonic hedgehog (SHH) signaling pathway in the regulatory effects of HO-1 on PC progression were examined. For this purpose, the expression of HO-1 was examined in cultured PC cells by real-time PCR, western blot analysis and immunofluorescence. Transfection with small interfering RNA against HO-1 or an overexpression plasmid were used to regulate the expression of HO-1 in the MIA PaCa-2 and PANC-1 cell lines. Cell proliferation was examined by MTT assays in response to the different treatments. The results revealed that HO-1 expression differed significantly in the different PC cells. The overexpression of HO-1 induced PC cell proliferation and the inhibition of HO-1 decreased the cell proliferative ability. Furthermore, HO-1 activated the SHH signaling pathway in the PC cells. In addition, the SHH signaling pathway was found to play a role in HO-1-induced PC cell proliferation. The inhibition of HO-1 enhanced the responsiveness of PC cells to Gem and Gem was found to regulate the expression of HO-1 and the activation of the SHH pathway. On the whole, our findings indicate that HO-1 overexpression in PC cells may be responsible for the increased cell proliferation and the resistance to anticancer therapy. Furthermore, the SHH signaling pathway, the activation of which was initiated by HO-1, may be one of the endogenous mechanisms in this process. Our data shed light into the association between HO-1 and SHH in PC cells, and may aid in the development of novel therapeutic targets for the treatment of patients with PC.

Elongator promotes the migration and invasion of hepatocellular carcinoma cell by the phosphorylation of AKT

The Elongator is a complex with multiple subunits (Elp1-Elp6) which promotes transcript elongation and protein translation. In this study, we investigated the effects of Elongator on the migration and invasion of HCC cells as well as the underlying mechanisms. We showed that overexpression of Elp3 or Elp4 promoted the migration and invasion of HCC cells, which was abolished when either Elp3 or Elp4 was silenced. The expression of matrix metalloproteinase-2 (MMP-2) and MMP-9 were enhanced by phosphorylation of AKT. Elongator-driven migration and invasion and the expression of MMP-2 and MMP-9 were reduced in HCC cells treated with AKT inhibitor LY294002. Depletion of Elp3 also reduced the phosphorylation of AKT induced by growth factors. In vivo assay of lung metastasis in mice demonstrated that overexpression of Elp3 increased tumor nodules metastatic to lung. Importantly, Elp3 was up-regulated in human HCC tissues, which was correlated with the phosphorylation of AKT and expression of MMP-2. Collectively, these results suggested that Elongator activated migration and invasion of HCC cells by promoting the expression of MMP-2 and MMP-9 through the PI3K/AKT signaling pathway. Our work suggests that Elongator might be a potential marker which promotes the metastasis of HCC.

Prognostic and clinicopathological value of Gli-1 expression in gastric cancer: A meta-analysis

Glioma associated oncogene-1 (Gli-1) is considered as a strong positive activator of downstream target genes of hedgehog signal pathway in mammalians. However, its diagnostic and prognostic value in gastric cancer remains unclear and controversial. Therefore, a quantitative meta-analysis was conducted to determine the clinical value of Gli-1 in gastric cancer patients. Twelve eligible articles with 886 gastric cancer patients were included in this meta-analysis. The relationship between Gli-1 expression in gastric cancer patients and clinicopathological features and 5-year overall survival (OS) was evaluated using pooled odds ratios (ORs) and hazard ratio (HR) with 95% confidence intervals (CIs). The meta-analysis showed that the upregulated Gli-1 was associated with sample type (gastric cancer tissues) (OR 10.31, 95%CI 7.14-14.88; P = 0.000), differentiation type (OR 3.76, 95%CI 2.55-5.53; P = 0.000), depth of invasion (OR 8.17, 95%CI 3.60-18.55; P = 0.000), lymph node metastasis (OR 3.97, 95%CI 2.73-5.78; P = 0.000) and high TNM stage (OR 3.65, 95%CI 1.89-7.04; P = 0.000). Three studies including 316 patients were assessed for the correlation between Gli-1 and 5-year OS, which indicated that positive Gli-1 expression was associated with poor prognosis in gastric cancer patients (HR 2.14, 95%CI 1.35-3.40; P = 0.001). Little publication bias was identified by funnel plots and Egger's tests. The sensitivity analysis indicated that no study substantially influenced pooled OR/HR. Taken together, Gli-1 is a credible indicator for highly aggressive tumor with poor prognosis in gastric cancer patients.

Molecular mechanisms underlying the antimetastatic activity of bufalin

Bufalin is a monomer compound extract from Chansu, which is a traditional Chinese medicine obtained from the skin and parotid venom glands of toads, such as Bufo bufo gargarizans Cantor and Bufo melanostictus Schneider. Chansu had been used in traditional Chinese medicine for >1,000 years due to its cardiac, anti-inflammatory and anticancer properties. Previous studies identified bufalin as the main anticancer compound of Chansu, and recent evidence has corroborated its anticancer properties. Bufalin inhibits cancer cell proliferation, induces cell cycle arrest, induces cancer cell apoptosis, inhibits neovascularization, induces cell differentiation, inhibits cancer metastasis and invasion, and enhances chemotherapeutic drug sensitivity. However, the function and mechanism of bufalin in metastatic cancer cells have not yet been expounded. The aim of the present review was to discuss the recent progress and prospects of bufalin in the prevention of cancer metastasis, particularly in inhibiting epithelial-to-mesenchymal transition.

Acquired resistance to BRAF inhibition induces epithelial-to-mesenchymal transition in BRAF (V600E) mutant thyroid cancer by c-Met-mediated AKT activation

Previously, the authors have identified that c-Met mediates reactivation of the PI3K/AKT pathway following BRAF inhibitor treatment in BRAF (V600E) mutant anaplastic thyroid cancer, thereby contributing to the acquired drug resistance. Therefore dual inhibition of BRAF and c-Met led to sustained treatment response, thereby maximizing the specific anti-tumor effect of targeted therapy. The present study goes one step further and aims to investigate the effect of acquired resistance of BRAF inhibitor on epithelial-to-mesenchymal transition (EMT) in BRAF mutant thyroid cancer cells and the effect of dual inhibition from combinatorial therapy. Two thyroid cancer cell lines, 8505C and BCPAP were selected and treated with BRAF inhibitor, PLX4032 and its effect on EMT were examined and compared. Further investigation was carried out in orthotopic xenograft mouse models. Unlike BCPAP cells, the BRAF inhibitor resistant 8505C cells showed increased expressions of EMT related markers such as vimentin, β-catenin, and CD44. The combinatorial treatment of PLX4032 and PHA665752, a c-Met inhibitor reversed EMT. Similar results were confirmed in vivo. c-Met-mediated reactivation of the PI3K/AKT pathway contributes to the drug resistance to PLX4032 in BRAF (V600E) mutant anaplastic thyroid cancer cells and further promotes tumor cell migration and invasion by upregulated EMT mechanism. Dual inhibition of BRAF and c-Met leads to reversal of EMT, suggesting a maximal therapeutic response.

Signaling pathways and mesenchymal transition in pediatric high-grade glioma

Pediatric high-grade gliomas (pHGG), including diffuse intrinsic pontine gliomas (DIPG), are the most lethal types of cancer in children. In recent years, it has become evident that these tumors are driven by epigenetic events, mainly mutations involving genes encoding Histone 3, setting them apart from their adult counterparts. These tumors are exceptionally resistant to chemotherapy and respond only temporarily to radiotherapy. Moreover, their delicate location and diffuse growth pattern make complete surgical resection impossible. In many other forms of cancer, chemo- and radioresistance, in combination with a diffuse, invasive phenotype, are associated with a transcriptional program termed the epithelial-to-mesenchymal transition (EMT). Activation of this program allows cancer cells to survive individually, invade surrounding tissues and metastasize. It also enables them to survive exposure to cytotoxic therapy, including chemotherapeutic drugs and radiation. We here suggest that EMT plays an important, yet poorly understood role in the biology and therapy resistance of pHGG and DIPG. This review summarizes the current knowledge on the major signal transduction pathways and transcription factors involved in the epithelial-to-mesenchymal transition in cancer in general and in pediatric HGG and DIPG in particular. Despite the fact that the mesenchymal transition has not yet been specifically studied in pHGG and DIPG, activation of pathways and high levels of transcription factors involved in EMT have been described. We conclude that the mesenchymal transition is likely to be an important element of the biology of pHGG and DIPG and warrants further investigation for the development of novel therapeutics.

Sotetsuflavone suppresses invasion and metastasis in non-small-cell lung cancer A549 cells by reversing EMT via the TNF-α/NF-κB and PI3K/AKT signaling pathway

Epithelial-mesenchymal transition (EMT) is associated with tumor invasion and metastasis, and offers insight into novel strategies for cancer treatment. Sotetsuflavone was isolated from Cycas revolute, which has excellent anticancer activity in the early stages. The present study aims to evaluate the anti-metastatic potential of sotetsuflavone in vitro. Our data demonstrated that sotetsuflavone inhibits metastasis of A549 cells, and EMT. This inhibition was reflected in the upregulation of E-cadherin, and downregulation of N-cadherin, vimentin, and Snail. Mechanistically, our study demonstrated that HIF-1α played an important role in the anti-metastatic effect of sotetsuflavone in non-small-cell lung cancer A549 cells. Sotetsuflavone not only mediated VEGF expression but also downregulated VEGF and upregulated angiostatin, and simultaneously affected the expression of MMPs and decreased MMP-9 and MMP-13 expression. More importantly, HIF-1α expression may be regulated by the inhibition of PI3K/AKT and TNF-α/NF-κB pathways. These results suggest that sotetsuflavone can reverse EMT, thereby inhibiting the migration and invasion of A549 cells. This process may be associated with both PI3K/AKT and TNF-α/NF-κB pathways, and sotetsuflavone may be efficacious in the treatment of non-small-cell lung cancer.

LAMB3 mediates metastatic tumor behavior in papillary thyroid cancer by regulating c-MET/Akt signals

Laminin subunit beta-3 (LAMB3) encodes one of the three subunits of LM-332, a protein of the extracellular matrix secreted by cultured human keratinocytes. While LAMB3 is involved in the invasive and metastatic abilities of several tumor types, including those found in the colon, pancreas, lung, cervix, stomach, and prostate, its mechanism of action in thyroid cancer has not been investigated previously. Our results show that LAMB3 is up-regulated in papillary thyroid cancer, and that its suppression reduces cell migration/invasion via down-regulation of epithelial‒mesenchymal transition-associated proteins (N-cadherin, vimentin, slug) and inhibition of matrix metalloproteinase 9. LAMB3 suppression also significantly decreases Akt phosphorylation and inhibits the transcription of c-MET, reducing its activation. These results suggest that LAMB3 leads to tumor invasion via Akt activation induced by the HGF/c-MET axis in papillary thyroid cancer cells. Our findings reveal a novel mechanism of action for LAMB3 in papillary thyroid cancer cells.

Nobiletin inhibits human osteosarcoma cells metastasis by blocking ERK and JNK-mediated MMPs expression

Nobiletin, a polymethoxyflavone, has a few pharmacological activities, including anti-inflammation and anti-cancer effects. However, its effect on human osteosarcoma progression remains uninvestigated. Therefore, we examined the effectiveness of nobiletin against cellular metastasis of human osteosarcoma and the underlying mechanisms. Nobiletin, up to 100 μM without cytotoxicity, significantly decreased motility, migration and invasion as well as enzymatic activities, protein levels and mRNA expressions of matrix metalloproteinase (MMP)-2 and MMP-9 in U2OS and HOS cells. In addition to inhibition of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), the inhibitory effect of nobiletin on the DNA-binding activity of the transcription factor nuclear factor-kappa B (NF-κB), cAMP response element-binding protein (CREB), and specificity protein 1 (SP-1) in U2OS and HOS cells. Co-treatment with ERK and JNK inhibitors and nobiletin further reduced U2OS cells migration and invasion. These results indicated that nobiletin inhibits human osteosarcoma U2OS and HOS cells motility, migration and invasion by down-regulating MMP-2 and MMP-9 expressions via ERK and JNK pathways and through the inactivation of downstream NF-κB, CREB, and SP-1. Nobiletin has the potential to serve as an anti-metastatic agent for treating osteosarcoma.

Sinomenine reduces growth and metastasis of breast cancer cells and improves the survival of tumor-bearing mice through suppressing the SHh pathway

In this study, the suppressive effect of sinomenine on the activation of SHh and the progression of breast cancer metastasis in vitro and in vivo was investigated. MDA-MB-231 breast cancer cells were treated with sinomenine and/or cyclopamine a proven SHh inhibitor. Sinomenine and cyclopamine both suppressed cell proliferation and migration, but sinomenine had a stronger suppressive effect in MDA-MB-231. In addition, sinomenine could suppress the activation of NF-κB and SHh signaling pathways, but cyclopamine could not suppress the activation of NF-κB. Subsequently, a mouse breast cancer-lung metastasis model was established. Our data on tissue examination and gene detection showed that SHh signaling was markedly activated in the metastatic model mice. The progression of lung metastasis was suppressed when mice were fed sinomenine and/or cyclopamine, while sinomenine had a stronger suppressive effect than cyclopamine in the model mice. In conclusion, sinomenine has a better effect than cyclopamine on the inhibition of breast cancer metastasis to lung in vivo and vitro, and inhibits NF-κB activation and NF-κB-mediated activation of SHh signaling pathway.

Strategies to Target Matrix Metalloproteinases as Therapeutic Approach in Cancer

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that are capable of degrading numerous extracellular matrix (ECM) components thus participating in physiological and pathological processes. Apart from the remodeling of ECM, they affect cell-cell and cell-matrix interactions and are implicated in the development and progression of various diseases such as cancer. Numerous studies have demonstrated that MMPs evoke epithelial to mesenchymal transition (EMT) of cancer cells and affect their signaling, adhesion, migration and invasion to promote cancer cell aggressiveness. Various studies have suggested MMPs as suitable targets for treatment of malignancies, and several MMP inhibitors (MMPIs) have been developed. Although initial trials have failed to establish MMPIs as anticancer agents due to lack of specificity and side effects, new MMPIs have been developed with improved action that are currently being investigated. Furthermore, novel strategies that target MMPs for improving drug delivery and regulating their activity in tumors are presented. This review summarizes the implication of MMPs in cancer progression and discusses the advancements in their targeting.

GABRA3 promotes lymphatic metastasis in lung adenocarcinoma by mediating upregulation of matrix metalloproteinases

Tumor metastasis is the main reason for the poor prognosis of lung cancer patients. The GABAA receptor subunit GABR_A3 is reportedly upregulated in lung cancer. Herein, we show that high GABR_A3 protein expression in lung adenocarcinoma correlated positively with disease stage, lymphatic metastasis status and poor patient survival. In addition, GABR_A3 induced MMP-2 and MMP-9 expression through activation of the JNK/AP-1 signaling pathway, which enhanced lymphatic metastasis by lung adenocarcinoma both in vitro and in vivo. These results indicate that GABR_A3 promotes lymph node metastasis and may thus be an effective therapeutic target for anticancer treatment.

Regulation of Hedgehog Signaling in Cancer by Natural and Dietary Compounds

The aberrant Hedgehog (Hh) signaling induced by mutations or overexpression of the signaling mediators has been implicated in cancer, associated with processes including inflammation, tumor cell growth, invasion, and metastasis, as well as cancer stemness. Small molecules targeting the regulatory components of the Hh signaling pathway, especially Smoothened (Smo), have been developed for the treatment of cancer. However, acquired resistance to a Smo inhibitor vismodegib observed in clinical trials suggests that other Hh signaling components need to be explored as potential anticancer targets. Natural and dietary compounds provide a resource for the development of potent agents affecting intracellular signaling cascades, and numerous studies have been conducted to evaluate the efficacy of natural products in targeting the Hh signaling pathway. In this review, we summarize the role of Hh signaling in tumorigenesis, discuss results from recent studies investigating the effect of natural products and dietary components on Hh signaling in cancer, and provide insight on novel small molecules as potential Hh signaling inhibitors.

Aberrant expression of STYK1 and E-cadherin confer a poor prognosis for pancreatic cancer patients

Previous studies showed that aberrant Serine/threonine/tyrosine kinase 1 (STYK1, also known as NOK) or/and E-cadherin were involved in the progression of some types of human cancers. However, whether they contributed to the development of pancreatic cancer was unknown. Here, we investigated the prognostic significance of aberrant STYK1 and E-cadherin in pancreatic cancer. Our results showed that STYK1 expression increased while E-cadherin decreased in pancreatic cancer tissues compared with normal pancreas tissues. STYK1 level was positively correlated with lymph node metastasis and clinical stage in pancreatic cancer patients. E-cadherin expression was inversely correlated with STYK1 expression in pancreatic cancer tissue samples. Patients with high STYK1 and low E-cadherin expression had the worst prognosis. In addition, STYK1 knockdown in pancreatic cancer cell lines inhibited cell proliferation, enhanced cell apoptosis, induced cell cycle arrest, and prohibited cell migration, while STYK1 over-expression showed the opposite effects. Silencing STYK1 also increased E-cadherin expression and inhibited epithelial-to-mesenchymal transition (EMT) and p-p38 expression in vitro. Over-expression had showed the opposite trends, and treatment with p38 inhibitor, SB203580, could reverse the trends. Thus, STYK1 repressed E-cadherin expression and promoted EMT, mediated by p38 MAPK signaling pathway, which was the possible mechanism for STYK1-mediated pancreatic cancer cell proliferation and migration. In summary, our results showed that STYK1 might be a prognostic marker for pancreatic cancer patients and might be a novel strategy for the treatment of pancreatic cancer.

Carcinoma associated fibroblasts derived from oral squamous cell carcinoma promote lymphangiogenesis via c-Met/PI3K/AKT in vitro

Carcinoma-associated fibroblasts (CAFs) are dominant components of the tumor microenvironment (TME) that promote the development, progression and metastasis of cancer. c-Met is a receptor of the hepatocyte growth factor (HGF), which is involved in lymphangiogenesis. Currently, the roles of CAFs during lymphangiogenesis are unknown. It has been hypothesized that CAFs contribute to lymphangiogenesis of oral squamous cell carcinoma (OSCC) via a HGF/c-Met complex. The expression of HGF in OSCC was determined using CAFs derived from OSCC tissue and it was demonstrated that HGF is overexpressed in OSCC-derived CAFs. It was also revealed that c-Met was highly expressed in human lymphatic endothelial cells (HLECs) when co-cultured with CAFs. Furthermore, it was demonstrated that recombinant human HGF significantly enhanced the proliferation, migration, invasion and tube formation of HLECs. By contrast, the inhibition of c-Met expression suppressed the aforementioned biological activities and also downregulated the expression of c-Met, phosphoinositide 3-kinase and phosphorylated protein kinase B. Taken together, these data demonstrate that c-Met is associated with the regulation of lymphangiogenesis. Thus, the results of the present study indicate that c-Met may be a promising novel therapeutic target to treat patients with OSCC.

QuaDMutEx: quadratic driver mutation explorer

BACKGROUND

Somatic mutations accumulate in human cells throughout life. Some may have no adverse consequences, but some of them may lead to cancer. A cancer genome is typically unstable, and thus more mutations can accumulate in the DNA of cancer cells. An ongoing problem is to figure out which mutations are drivers - play a role in oncogenesis, and which are passengers - do not play a role. One way of addressing this question is through inspection of somatic mutations in DNA of cancer samples from a cohort of patients and detection of patterns that differentiate driver from passenger mutations.

RESULTS

We propose QuaDMutEx, a method that incorporates three novel elements: a new gene set penalty that includes non-linear penalization of multiple mutations in putative sets of driver genes, an ability to adjust the method to handle slow- and fast-evolving tumors, and a computationally efficient method for finding gene sets that minimize the penalty, through a combination of heuristic Monte Carlo optimization and exact binary quadratic programming. Compared to existing methods, the proposed algorithm finds sets of putative driver genes that show higher coverage and lower excess coverage in eight sets of cancer samples coming from brain, ovarian, lung, and breast tumors.

CONCLUSIONS

Superior ability to improve on both coverage and excess coverage on different types of cancer shows that QuaDMutEx is a tool that should be part of a state-of-the-art toolbox in the driver gene discovery pipeline. It can detect genes harboring rare driver mutations that may be missed by existing methods. QuaDMutEx is available for download from https://github.com/bokhariy/QuaDMutEx under the GNU GPLv3 license.

TIPE1 suppresses invasion and migration through down-regulating Wnt/β-catenin pathway in gastric cancer

Epithelial–mesenchymal transition (EMT) plays an important role in the invasiveness and metastasis of gastric cancer. Therefore, identifying key molecules involved in EMT will provide new therapeutic strategy for treating patients with gastric cancer. TIPE1 is a newly identified member of the TIPE (TNFAIP8) family, and its contributions to progression and metastasis have not been evaluated. In this study, we found that the levels of TIPE1 were significantly reduced and inversely correlated with differentiation status and distant metastasis in primary gastric cancer tissues. We further observed overexpression of TIPE1 in aggressive gastric cancer cell lines decreased their metastatic properties both in vitro and in vivo as demonstrated by markedly inhibiting EMT and metastasis of gastric cancer cells in nude mice. Consistently, gene silencing of TIPE1 in well‐differentiated gastric cancer cell line (AGS) inhibited these processes. Mechanistically, we found that TIPE1‐medicated Wnt/β‐catenin signalling was one of the critical signal transduction pathways that link TIPE1 to EMT inhibition. Importantly, TIPE1 dramatically restrained the expression and activities of MMP2 and MMP9 which are demonstrated to promote tumour progression and are implicated in EMT. Collectively, these findings provide new evidence for a better understanding of the biological activities of TIPE1 in progression and metastasis of gastric cancer and suggest that TIPE1 may be an innovative diagnostic and therapeutic target of gastric cancer.

Sonic hedgehog (SHH) signaling improves the angiogenic potential of Wharton's jelly-derived mesenchymal stem cells (WJ-MSC)

Background

Wharton’s jelly-derived mesenchymal stem cells (WJ-MSC) show remarkable therapeutic potential to repair tissue upon injury via paracrine signaling by secreting diverse trophic factors that promote angiogenesis. However, the mechanisms and signaling pathways that regulate the induction of these specific factors are still mostly unknown. Emerging evidence suggests that Sonic hedgehog (SHH) plays a central role in angiogenesis and tissue maintenance. However, its contribution to the angiogenic potential of MSC has not been fully addressed. The aim of this work was to characterize the expression of the SHH pathway components in WJ-MSC primary cultures and to evaluate their angiogenic responsiveness to SHH signaling.

Methods

Primary cell cultures obtained from human umbilical cords were treated with pharmacological modulators of the SHH pathway. We evaluated the modulation of diverse trophic factors in cell lysates, conditioned medium, and functional in vitro assays. In addition, we determined the angiogenic potential of the SHH pathway in the chicken chorioallantoic membrane, an in vivo model.

Results

Our results show that WJ-MSC express components of the canonical SHH pathway and are activated by its signaling. In fact, we provide evidence of basal autocrine/paracrine SHH signaling in WJ-MSC. SHH pathway stimulation promotes the secretion of angiogenic factors such as activin A, angiogenin, angiopoietin 1, granulocyte-macrophage colony-stimulating factor, matrix metallometallopeptidase -9, and urokinase-type plasminogen activator, enhancing the pro-angiogenic capabilities of WJ-MSC both in vitro and in vivo.

Conclusion

WJ-MSC are a cell population responsive to SHH pathway stimulation. Basal SHH signaling is in part responsible for the angiogenic inductive properties of WJ-MSC. Overall, exogenous activation of the SHH pathway enhances the angiogenic properties of WJ-MSC, making this cell population an ideal target for treating tissue injury.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0653-8) contains supplementary material, which is available to authorized users.

Targeting epithelial-mesenchymal plasticity in cancer: clinical and preclinical advances in therapy and monitoring

The concept of epithelial-mesenchymal plasticity (EMP), which describes the dynamic flux within the spectrum of phenotypic states that invasive carcinoma cells may reside, is being increasingly recognised for its role in cancer progression and therapy resistance. The myriad of events that are able to induce EMP, as well as the more recently characterised control loops, results in dynamic transitions of cancerous epithelial cells to more mesenchymal-like phenotypes through an epithelial-mesenchymal transition (EMT), as well as the reverse transition from mesenchymal phenotypes to an epithelial one. The significance of EMP, in its ability to drive local invasion, generate cancer stem cells and facilitate metastasis by the dissemination of circulating tumour cells (CTCs), highlights its importance as a targetable programme to combat cancer morbidity and mortality. The focus of this review is to consolidate the existing knowledge on the strategies currently in development to combat cancer progression via inhibition of specific facets of EMP. The prevalence of relapse due to therapy resistance and metastatic propensity that EMP endows should be considered when designing therapy regimes, and such therapies should synergise with existing chemotherapeutics to benefit efficacy. To further improve upon EMP-targeted therapies, it is imperative to devise monitoring strategies to assess the impact of such treatments on EMP-related phenomenon such as CTC burden, chemosensitivity/-resistance and micrometastasis in patients.

Basal cell carcinoma pathogenesis and therapy involving hedgehog signaling and beyond

Basal cell carcinoma (BCC) of the skin is driven by aberrant hedgehog signaling. Thus blocking this signaling pathway by small molecules such as vismodegib inhibits tumor growth. Primary cilium in the epidermal cells plays an integral role in the processing of hedgehog signaling-related proteins. Recent genomic studies point to the involvement of additional genetic mutations that might be associated with the development of BCCs, suggesting significance of other signaling pathways, such as WNT, NOTCH, mTOR, and Hippo, aside from hedgehog in the pathogenesis of this human neoplasm. Some of these pathways could be regulated by noncoding microRNA. Altered microRNA expression profile is recognized with the progression of these lesions. Stopping treatment with Smoothened (SMO) inhibitors often leads to tumor reoccurrence in the patients with basal cell nevus syndrome, who develop 10-100 of BCCs. In addition, the initial effectiveness of these SMO inhibitors is impaired due to the onset of mutations in the drug-binding domain of SMO. These data point to a need to develop strategies to overcome tumor recurrence and resistance and to enhance efficacy by developing novel single agent-based or multiple agents-based combinatorial approaches. Immunotherapy and photodynamic therapy could be additional successful approaches particularly if developed in combination with chemotherapy for inoperable and metastatic BCCs.

ERp29 inhibits tumorigenicity by suppressing epithelial mesenchymal transition in gastric cancer

ERp29 is a novel endoplasmic reticulum (ER) protein that plays an important role in protein unfolding and secretion. Recently, it has been reported to be widely implicated in control of tumorigenesis in some tumors. However, the potential function of ERp29 in gastric cancer remains poorly understood. In this study, we found that the positive rate of ERp29 in gastric cancer tissues was significantly lower than that in adjacent non-tumor tissues. And tumor with high ERp29 expression had inclinations towards smaller tumor size and earlier TNM stage. The in vitro experiments indicated that over-expression of ERp29 in gastric cancer cells significantly suppressed the proliferation and migration of tumor cells, which is consistent with the result of the in vivo animal experiments. Furthermore, our mechanistic investigations revealed that ERp29 reversed EMT process in gastric carcinoma, and its effect was related to the inactivation of ERK1/2 and AKT phosphorylation. Thus, we conclude that ERp29 acts as a tumor suppressor gene in gastric cancer, and is expected to become a novel target of the treatment of GC.

Blockade of sonic hedgehog signaling decreases viability and induces apoptosis in retinoblastoma cells: The key role of the PI3K/Akt pathway

Retinoblastoma (RB) is the most common type of malignant intraocular cancer in teenagers. One of the proteins abnormally expressed during oncogenesis of RB is sonic hedgehog (SHH), which possesses the capability to selectively activate transcription factors of different genes. However, the detailed function of SHH in RB remains unknown. Thus, the present study sought to investigate the role of SHH in the development of RB. The human RB WERI-Rb-1 cell line was used as an in vitro model for the knockdown of SHH by a specific short hairpin RNA (shRNA). To assess the effect of SHH inhibition on cell growth and apoptosis, cell viability, colony formation and flow cytometry assays were conducted. WERI-Rb-1 cells transfected with an shRNA targeting SHH were treated with the phosphoinositide-3 kinase (PI3K)/Akt agonist insulin-like growth factor 1 (IGF-1) to investigate the possible mechanism by which SHH promotes RB. The present results revealed that the silencing of SHH induced G1 cell-cycle arrest and apoptosis in WERI-Rb-1 cells and led to a decrease in cell viability, indicating that SHH has a critical role in the determination of RB cell survival. Moreover, according to the results of the IGF-1 assays, suppression of PI3K/Akt was a prerequisite for SHH inhibition, illuminating its potential role in the treatment of RB. The findings outlined in the present study elucidate a clear link between SHH and the PI3K/Akt pathway in RB cell survival, which could provide valuable inspiration for the advancement of therapies against RB.

Duchesnea indica extract suppresses the migration of human lung adenocarcinoma cells by inhibiting epithelial-mesenchymal transition

Epithelial-mesenchymal transition (EMT) is a process through which epithelial cells are transformed into mesenchymal cells; EMT diminishes cell polarity and cell-cell adhesion in cancer cells, leading to enhanced migratory and invasive properties. In this experiment, zymography, cell invasion, and migration assays were performed. Results indicated that Duchesnea indica extracts (DIE) inhibited highly metastatic A549 and H1299 cells by reducing the secretions of matrix metalloproteinase-2 and urokinase-type plasminogen activator. Cell adhesion assay also demonstrated that DIE reduced the cell adhesion properties. Western blot analysis showed that DIE down-regulated the expression of N-cadherin, fibronectin, and vimentin, which are mesenchymal markers, and enhanced that of E-cadherin, which is an epithelial marker. In vivo study showed that tumor growth was significantly reduced in BALB/c nude mouse xenograft model administered with oral gavage of DIE. Therefore, DIE could be exhibits potential as a phytochemical-based platform for prevention and treatment of lung cancer. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 2053-2063, 2017.

Arl13b Promotes Gastric Tumorigenesis by Regulating Smo Trafficking and Activation of the Hedgehog Signaling Pathway

Inhibitors of the Hedgehog (Hh) pathway transducer Smoothened (Smo) have been approved for cancer treatment, but Smo mutations often lead to tumor resistance and it remains unclear how Smo is regulated. In this study, we identified the small GTPase Arl13b as a novel partner and regulator of Smo. Arl13b regulated Smo stability, trafficking, and localization, which are each crucial for Hh signaling. In gastric cancer cells, Arl13b stimulated proliferation, migration, and invasion in vitro and in vivo In clinical specimens of gastric cancer, Arl13b expression correlated strongly with tumor size and depth of invasion; patients with high levels of Arl13b had a poor prognosis. Our results show how Arl13b participates in Hh pathway activation in gastric cancer. Cancer Res; 77(15); 4000-13. ©2017 AACR.

Combination treatment with dendrosomal nanocurcumin and doxorubicin improves anticancer effects on breast cancer cells through modulating CXCR4/NF-κB/Smo regulatory network

Despite advantageous antitumor properties of doxorubicin, the considerable cytotoxicity of this chemotherapeutic agent has made it necessary to develop combination treatment strategies. The aim of the current study was to investigate the possible synergism between dendrosomal nanocurcumin (DNC) and doxorubicin in eliciting anticancer effects on MDA-MB-231 metastatic breast cancer cells. The expression levels of CXCL12/CXCR4 axis and Hedgehog pathway genes were evaluated in patient-derived breast carcinoma tissues by qRT-PCR. MTT assay, Annexin V-FITC staining followed by flowcytomety and wound healing assay were used to measure the effects caused by DNC and doxorubicin, alone and in combination, on the viability, apoptosis induction, and migration of MDA-MB-231 cells, respectively. Also, qRT-PCR was exploited to analyze the expression of Smo, NF-κB and CXCR4 in cancer cells. Our results revealed that combination treatment with DNC and doxorubicin leads to significantly decreased viability, increased apoptosis, and reduced migration of breast cancer cells compared with using each drug alone. Also, combination treatment is more efficient that single treatment in reducing the expression levels of NF-κB and Smo transcripts. Our findings provide convincing support for the notion that DNC could synergistically enhance the anticancer effects of doxorubicin on metastatic breast cancer cells by improving its anti-proliferative, pro-apoptotic, and anti-migratory activities. This may be mediated, in part, by downregulating CXCR4, NF-κB, and Smo genes. Overall, the findings of the current study suggest that DNC might be used as a synergistic agent for enhancing therapeutic efficiency and reducing toxic effects of doxorubicin on breast cancer cells.

Cinnamomum cassia extracts reverses TGF-β1-induced epithelial-mesenchymal transition in human lung adenocarcinoma cells and suppresses tumor growth in vivo

Metastasis is the most common cause of cancer-related mortality in patients, and epithelial-mesenchymal transition (EMT) is essential for cancer metastasis and antidrug resistance. Cinnamomum cassia has several antioxidative, anti-inflammatory, and anticancer biological effects. However, the anti-EMT effect of C. cassia in human lung carcinoma is rarely reported. In this study, we determined whether C. cassia extracts (CCE) reduces the EMT and tumor growth of human lung adenocarcinoma cells. CCE inhibited the transforming growth factor (TGF)-β1-induced cell motility and invasiveness of A549 and H1299 cells by repressing matrix metalloproteinase-2 and urokinase-type plasminogen activator as well as impaired cell adhesion to collagen. CCE also affected the TGF-β1-induced EMT by downregulating the expression of vimentin and fibronectin and upregulating E-cadherin. The nude mice xenograft model showed that CCE reduced A549 tumor growth. Thus, CCE possesses antimetastatic activity of A549 and H1299 cells by affecting EMT and suppressing A549 tumor growth in vivo. This result suggested that CCE could be used as an antimetastatic agent or as an adjuvant for anticancer therapy.

Human CAFs promote lymphangiogenesis in ovarian cancer via the Hh-VEGF-C signaling axis

Cancer-associated fibroblasts (CAFs) play a pivotal role in the development and progression of many human cancers. Recent studies have shown that Hedgehog (Hh) signalling modulates the stromal microenvironment and prepares a suitable niche for tumour metastasis. However, the detailed molecular mechanisms underlying CAF-mediated lymphangiogenesis have not been fully elucidated. Therefore, our goal is to illustrate whether Hh ligands can activate Hh signalling in CAFs in a paracrine fashion and elucidate the effect of CAFs on lymphangiogenesis. We determined here that Sonic Hedgehog (SHH) secreted by ovarian cancer (OC) cells activated Hh signalling in CAFs and promoted the proliferation of CAFs. Moreover, we co-injected SHH-overexpressing OC cells and CAFs in a xenograft model and found that the CAFs accelerated tumourigenesis and lymphangiogenesis in OC. Mechanistically, we found that SHH secreted by the OC cells induced VEGF-C expression in CAFs. Inhibition of Hh signalling in CAFs decreased VEGF-C expression and diminished the positive role of CAFs in supporting tumourigenesis and lymphangiogenesis in a murine xenograft model. Our results demonstrate that CAFs constitute a supportive niche for cancer lymphangiogenesis via the Hh/VEGF-C signalling axis and provide evidence for the clinical application of Hh inhibitors in the treatment of OC.

Silencing IGFBP-2 decreases pancreatic cancer metastasis and enhances chemotherapeutic sensitivity

Pancreatic cancer has remained one of the most devastating and lethal malignancies characterized by local invasion, distant metastasis and a high degree of chemoresistance. Insulin-like growth factor binding protein 2 (IGFBP-2) is a member of the IGFBP family of proteins, and it is highly expressed in pancreatic cancer patients’ serum and tumor tissues. IGFBP-2 also mediates tumor cell growth, invasion and resistance, while the mechanisms remain unclear. In this study, we sought to determine the impact of IGFBP-2 expression on pancreatic cancer tumorigenesis and metastasis in vitro and in vivo. Wound healing, migration and invasion assays revealed that knockdown of IGFBP-2 inhibits cancer cell migration and invasion. Downregulation of IGFBP-2 attenuates EMT via increasing the E-cadherin and reducing the vimentin and N-cadherin. PTCH-1 is found contribute to the function of IGFBP-2 in suppressing metastasis and EMT of pancreatic cancer. Silencing IGFBP-2 inhibited invasion and metastatic properties, partially through inhibiting PTCH1 in pancreatic cancer. Additionally, inhibition of IGFBP-2 enhanced the sensitivity of pancreatic cancer cells to gemcitabine, suppressed tumor growth and potentiated the anti-tumor effect of gemcitabine in the orthotopic tumor model. Our results provide novel insight of IGFBP-2 as a promising target to inhibit the metastasis and overcome the chemoresistance in pancreatic cancer.

Curcumin increases efficiency of γ-irradiation in gliomas by inhibiting Hedgehog signaling pathway

It was reported that γ-irradiation had a controversial therapeutic effect on glioma cells. We aimed to investigate the cytotoxic effect on the glioma cells induced by γ-irradiation and explore the treatment to rescue the phenotype alteration of remaining cells. We used transwell assay to detect the glioma cell invasion and migration capacity. Cell proliferation and apoptosis were tested by the CCK-8 assay and flow cytometry respectively. Western Blot was used to detect the activity of Hedgehog signaling pathway and Epithelial-to-Mesenchymal Transition (EMT) status. γ-irradiation showed cytotoxic effect on LN229 cells in vitro, whereas this contribution was limited in U251 cells. However, it could significantly stimulated EMT process in both LN229 and U251. Curcumin (CCM) could rescue EMT process induced by γ-irradiation via the suppression of Gli1 and the upregulation of Sufu. The location and expression of EMT markers were also verified by Immunofluorescence. Immunohistochemistry assay was used on intracranial glioma tissues of nude mice. The capacities of cell migration and invasion were suppressed with combined therapy. This research showed Curcumin could rescue the EMT process induced by γ-irradiation via inhibiting the Hedgehog signaling pathway and potentiate the cell cytotoxic effect in vivo and in vitro.

Relationships of MMP-9, E-cadherin, and VEGF expression with clinicopathological features and response to chemosensitivity in gastric cancer

The matrix metalloproteinase-9, E-cadherin, and vascular endothelial growth factor play an important role in behavior of tumor cell growth, invasion, and metastasis. In this study, we investigated the relationships of matrix metalloproteinase-9, E-cadherin, and vascular endothelial growth factor expression with clinicopathological features and results of chemosensitivity tested by collagen gel droplet–embedded culture–drug sensitivity test in gastric cancer. Fresh specimens were used for collagen gel droplet–embedded culture–drug sensitivity test and paired fixed specimens were used for immunohistochemistry. Positive expression of matrix metalloproteinase-9 was associated with poorly differentiated carcinoma (p = 0.032), lymph node metastasis (p = 0.022), and tumor stage (p = 0.023). Negative expression of E-cadherin was associated with poorly differentiated carcinoma (p = 0.007), lymph node metastasis (p = 0.012), and tumor stage (p = 0.007). Positive expression of vascular endothelial growth factor was associated with tumor size (p = 0.040) and stage (p = 0.007). Collagen gel droplet–embedded culture–drug sensitivity test was successfully evaluated in 56 patients. Among them, 29 (51.7%) patients were resistant to TS-1 and 31 (55.3%) patients were resistant to L-OHP. The L-OHP resistance rate in vascular endothelial growth factor positive patients was significantly higher than that in negative patients (p = 0.031). The L-OHP resistance rate in E-cadherin negative patients was significantly higher than that in positive patients (p = 0.014). In conclusion, matrix metalloproteinase-9, E-cadherin, and vascular endothelial growth factor were involved in tumor invasion and metastasis. Positive expression of matrix metalloproteinase-9 and vascular endothelial growth factor and negative expression of E-cadherin were malignant markers for gastric cancer. Positive expression of vascular endothelial growth factor and negative expression of E-cadherin were associated with L-OHP resistance.

Genetics of Gastric Cancer

Gastric cancer represents a major cause of cancer mortality worldwide despite a declining incidence. New molecular classification schemes developed from genomic and molecular analyses of gastric cancer have provided a framework for understanding this heterogenous disease, and early findings suggest these classifications will be relevant for designing and implementing new targeted therapies. The success of targeted therapy and immunotherapy in breast cancer and melanoma, respectively, has not been duplicated in gastric cancer, but trastuzumab and ramucirumab have demonstrated efficacy in select populations. New markers that predict therapeutic response are needed to improve patient selection for both targeted and immunotherapies.

Smoothened antagonist GDC-0449 (Vismodegib) inhibits proliferation and triggers apoptosis in colon cancer cell lines

The sonic hedgehog (Shh) pathway has been proven to be involved in embryonic development and cancer growth. GDC-0449, an antagonist of the hedgehog signaling receptor Smoothened (Smo), was recently approved by the US Food and Drug Administration as a prescription for skin basal cell carcinoma. However, the efficacy of GDC-0449 in the treatment of colon cancer and other malignancies, such as basal cell carcinoma and pancreatic cancer, has remained to be proven. The present study assessed the effect of GDC-0449 on the colon cancer cell lines Caco-2 and Ht-29. A Cell Counting Kit-8 assay was applied to assess the cell proliferation rate and apoptosis was tested by flow cytometry. Reverse-transcription quantitative PCR and western blot analysis were used for analyzing expression levels of target genes. Cell proliferation was inhibited, while apoptosis was increased by GDC-0449, whereas the expression of B-cell lymphoma 2 (Bcl-2), a downstream target of Shh signaling, was decreased. Consistent with the inhibition of Gli1 expression, the cancer stem cell markers CD44 and ALDH were decreased in the presence of GDC-0449. In conclusion, GDC-0449 was shown to inhibit the replication of colon cancer cells and trigger apoptosis through downregulating Bcl-2. This may also influence the stemness of cancer stem cells as indicated by the decreased stem cell surface markers.

Molecular mechanism of C-reaction protein in promoting migration and invasion of hepatocellular carcinoma cells in vitro

Hepatocellular carcinoma (HCC) is one of most common malignant cancers and is the second leading cause of cancer related deaths. The prognosis and survival of patients are closely related to the degree of tumor metastasis. The mechanism of HCC metastasis is still unclear. In the present study, we investigated the molecular mechanism of C-reaction protein in promoting migration and invasion of hepatocellular carcinoma cells in vitro. We estimated that CRP is overexpressed in liver cancer tissues and that it promotes invasion and metastasis of HCC in vitro. In the present study, we employed iTRAQ-based mass spectrometry to analyze the HepG2 secretory proteins of CRP siRNA-treated cells and negative control siRNA-treated cells. We identified 109 differentially expressed proteins after silencing CRP, of which 45 were upregulated and 64 were downregulated. Some of the differentially expressed proteins were confirmed by western blot analysis and real-time quantitative PCR. Furthermore, we found that knockdown of CRP substantially abrogates HIF-1α expression levels, the luciferase activity of HIF-1α and ERK and Akt phosphorylation in HepG2 cells. The present study provides a novel mechanism by which CRP promotes the proliferation, migration, invasion and metastasis of hepatocellular carcinoma cells. Inhibition of CRP suppressed migration, invasion and healing of hepatoma carcinoma cells by decreasing HIF-1α activity and CTSD.

The FOXM1-ABCC5 axis contributes to paclitaxel resistance in nasopharyngeal carcinoma cells

Paclitaxel is clinically used as a first-line chemotherapeutic regimen for several cancer types, including head and neck cancers. However, acquired drug resistance results in the failure of therapy, metastasis and relapse. The drug efflux mediated by ATP-binding cassette (ABC) transporters and the survival signals activated by forkhead box (FOX) molecules are critical in the development of paclitaxel drug resistance. Whether FOX molecules promote paclitaxel resistance through drug efflux remains unknown. In this study, we developed several types of paclitaxel-resistant (TR) nasopharyngeal carcinoma (NPC) cells. These TR NPC cells acquired cancer stem cell (CSC) phenotypes and underwent epithelial to mesenchymal transition (EMT), and developed multidrug resistance. TR cells exhibited stronger drug efflux than parental NPC cells, leading to the reduction of intracellular drug concentrations and drug insensitivity. After screening the gene expression of ABC transporters and FOX molecules, we found that FOXM1 and ABCC5 were consistently overexpressed in the TR NPC cells and in patient tumor tissues. Further studies demonstrated that FOXM1 regulated abcc5 gene transcription by binding to the FHK consensus motifs at the promoter. The depletion of FOXM1 or ABCC5 with siRNA significantly blocked drug efflux and increased the intracellular concentrations of paclitaxel, thereby promoting paclitaxel-induced cell death. Siomycin A, a FOXM1 inhibitor, significantly enhanced in vitro cell killing by paclitaxel in drug-resistant NPC cells. This study is the first to identify the roles of FOXM1 in drug efflux and paclitaxel resistance by regulating the gene transcription of abcc5, one of the ABC transporters. Small molecular inhibitors of FOXM1 or ABCC5 have the potential to overcome paclitaxel chemoresistance in NPC patients.

Lymphangiogenesis and colorectal cancer

Lymphatic metastasis is an important event in the progress of metastasis in colorectal cancer (CRC). The purpose of this article is to assess the role of lymphangiogenesis on CRC. In peritumoral areas of CRC, the lymphatic microvessel density (LMVD) is higher than those in normal colorectal tissues. Morever, the high LMVD is correlated with DFS and local recurrence in CRC. The VEGF-C/VEGF-D/VEGFR-3 pathway, sonic hedgehog (Shh) signaling pathway and extracellular matrix (ECM) are involved in the regulation of lymphangiogenesis in CRC. Inhibition of the VEGF-C/VEGF-D/VEGFR-3 pathway by specific antibodies has been reported to efficiently inhibit experimental tumor lymphangiogenesis and metastasis in animal experiments. Although lymphangiogenesis has been reported to play an important role in the occurrence of colon cancer and to be associated with prognosis, it remains unclear whether it is a valid therapeutic target molecule. Further study of the potential of targeting this process for anti-lymphatic therapies is worthwhile.