Nestin is a novel target for suppressing pancreatic cancer cell migration, invasion and metastasis

Epithelial and Mesenchymal-like Pancreatic Cancer Cells Exhibit Different Stem Cell Phenotypes Associated with Different Metastatic Propensities

Pancreatic ductal adenocarcinoma (PDAC) is mostly diagnosed at advanced or even metastasized stages, limiting the prognoses of patients. Metastasis requires high tumor cell plasticity, implying phenotypic switching in response to changing environments. Here, epithelial-mesenchymal transition (EMT), being associated with an increase in cancer stem cell (CSC) properties, and its reversion are important. Since it is poorly understood whether different CSC phenotypes exist along the EMT axis and how these impact malignancy-associated properties, we aimed to characterize CSC populations of epithelial and mesenchymal-like PDAC cells. Single-cell cloning revealed CSC (Holoclone) and non-CSC (Paraclone) clones from the PDAC cell lines Panc1 and Panc89. The Panc1 Holoclone cells showed a mesenchymal-like phenotype, dominated by a high expression of the stemness marker Nestin, while the Panc89 Holoclone cells exhibited a SOX2-dominated epithelial phenotype. The Panc89 Holoclone cells showed enhanced cell growth and a self-renewal capacity but slow cluster-like invasion. Contrarily, the Panc1 Holoclone cells showed slower cell growth and self-renewal ability but were highly invasive. Moreover, cell variants differentially responded to chemotherapy. In vivo, the Panc1 and Panc89 cell variants significantly differed regarding the number and size of metastases, as well as organ manifestation, leading to different survival outcomes. Overall, these data support the existence of different CSC phenotypes along the EMT axis in PDAC, manifesting different metastatic propensities.

Nestin is a New Partner in Endothelial Colony Forming Cell Angiogenic Potential

Nestin, an intermediate filament protein expressed by progenitor cells, is associated with tissue regeneration. Although nestin expression has been reported in poorly differentiated and newly formed blood vessels, its role in endothelial cells remains unclear. In this study, we investigated the involvement of nestin in the angiogenic properties of endothelial colony-forming cells (ECFCs) derived from human umbilical cord blood. Our results demonstrate that ECFCs express high levels of nestin, and that its inhibition by small interfering RNAs decreased ECFC proliferation, migration in response to SDF-1 and VEGF-A, tubulogenesis, and adhesion on collagen. These effects are associated with modulation of focal adhesion kinase phosphorylation. Furthermore, nestin silencing resulted in reduced revascularization in a mouse hindlimb ischemia model. In conclusion, these findings provide evidence that nestin more than being a structural protein, is an active player in ECFC angiogenic properties.

Pancreatic cancer stemness: dynamic status in malignant progression

Pancreatic cancer (PC) is one of the most aggressive malignancies worldwide. Increasing evidence suggests that the capacity for self-renewal, proliferation, and differentiation of pancreatic cancer stem cells (PCSCs) contribute to major challenges with current PC therapies, causing metastasis and therapeutic resistance, leading to recurrence and death in patients. The concept that PCSCs are characterized by their high plasticity and self-renewal capacities is central to this review. We focused specifically on the regulation of PCSCs, such as stemness-related signaling pathways, stimuli in tumor cells and the tumor microenvironment (TME), as well as the development of innovative stemness-targeted therapies. Understanding the biological behavior of PCSCs with plasticity and the molecular mechanisms regulating PC stemness will help to identify new treatment strategies to treat this horrible disease.

Nestin Modulates Airway Smooth Muscle Cell Migration by Affecting Spatial Rearrangement of Vimentin Network and Focal Adhesion Assembly

Airway smooth muscle cell migration plays a role in the progression of airway remodeling, a hallmark of allergic asthma. However, the mechanisms that regulate cell migration are not yet entirely understood. Nestin is a class VI intermediate filament protein that is involved in the proliferation/regeneration of neurons, cancer cells, and skeletal muscle. Its role in cell migration is not fully understood. Here, nestin knockdown (KD) inhibited the migration of human airway smooth muscle cells. Using confocal microscopy and the Imaris software, we found that nestin KD attenuated focal adhesion sizes during cell spreading. Moreover, polo-like kinase 1 (Plk1) and vimentin phosphorylation at Ser-56 have been previously shown to affect focal adhesion assembly. Here, nestin KD reduced Plk1 phosphorylation at Thr-210 (an indication of Plk1 activation), vimentin phosphorylation at Ser-56, the contacts of vimentin filaments to paxillin, and the morphology of focal adhesions. Moreover, the expression of vimentin phosphorylation-mimic mutant S56D (aspartic acid substitution at Ser-56) rescued the migration, vimentin reorganization, and focal adhesion size of nestin KD cells. Together, our results suggest that nestin promotes smooth muscle cell migration. Mechanistically, nestin regulates Plk1 phosphorylation, which mediates vimenitn phosphorylation, the connection of vimentin filaments with paxillin, and focal adhesion assembly.

Evaluation of Clinical and Immunohistochemical Factors Relating to Melanoma Metastasis: Potential Roles of Nestin and Fascin in Melanoma

For melanoma treatment, an early diagnosis and a complete resection of the primary tumor is essential. In addition, detection of factors that may be related to metastasis is indispensable. A total of 30 Japanese patients with Stage I or II melanoma, diagnosed according to the classification of the American Joint Committee on Cancer, are included in this study. Clinical background (sex, onset age, primary tumor area, existence of remaining cancer cells at the resected tissue margin, and treatment after the primary surgery) and immunohistochemical staining (Nestin and Fascin) on the resected tissue were examined to detect factors statistically related to metastasis. The analysis result has shown that older onset age and positive immunohistochemical expressions of Nestin and Fascin are statistically related to metastasis. To facilitate meticulous observation of Nestin and Fascin expression at different timing (e.g., onset and metastasis), double immunofluorescence staining was performed. Nestin is a class VI intermediate filament protein, initially detected in neural stem cells. Fascin is an actin-bundling protein which regulates cell adhesion, migration and invasion. Nestin and Fascin are suggested to relate to melanoma metastasis, however, the potential role of Fascin is controversial. Analysis of variations in Fascin expression detected in this study may contribute to further investigations concerning potential roles of Fascin for progression of melanoma. This is the first study to report double immunofluorescent staining of Nestin and Fascin in melanoma. Nestin and Fascin double-positive melanoma cells were detected.

The Microbiome Tumor Axis: How the Microbiome Could Contribute to Clonal Heterogeneity and Disease Outcome in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant cancers. It is characterized by a poor prognosis with a 5-year survival rate of only around 10% and an ongoing increase in death rate. Due to the lack of early and specific symptoms, most patients are diagnosed at an advanced or even metastasized stage, essentially limiting curative treatment options. However, even curative resection of the primary tumor and adjuvant therapy often fails to provide a long-term survival benefit. One reason for this dismal situation can be seen in the evolution of therapy resistances. Furthermore, PDAC is characterized by high intratumor heterogeneity, pointing towards an abundance of cancer stem cells (CSCs), which are regarded as essential for tumor initiation and drug resistance. Additionally, it was shown that the gut microbiome is altered in PDAC patients, promotes Epithelial-Mesenchymal-Transition (EMT), determines responses towards chemotherapy, and affects survival in PDAC patients. Given the established links between CSCs and EMT as well as drug resistance, and the emerging role of the microbiome in PDAC, we postulate that the composition of the microbiome of PDAC patients is a critical determinant for the abundance and plasticity of CSC populations and thus tumor heterogeneity in PDAC. Unravelling this complex interplay might pave the way for novel treatment strategies.

Nestin Is Required for Spindle Assembly and Cell-Cycle Progression in Glioblastoma Cells

Nestin, a class IV intermediate filament protein, is generally considered as a putative marker of neural stem and progenitor cells in the central nervous system. Glioma is a common type of adult brain tumors, and glioblastoma (GBM) represents the most aggressive form of glioma. Here, we report that Nestin expression is significantly upregulated in human GBM, compared with other types of glioma. Nestin knockdown or deletion in U251 cells and tumor cells from GBM patients derived xenografts resulted in G2-M arrest, finally leading to apoptosis in tumor cells. Using proximity-dependent biotin identification method, we identified βII-tubulin as an interacting protein of Nestin in U251 cells. Nestin stabilized βII-tubulin in U251 cells through physical interaction. Knockdown of Nestin or βII-tubulin disrupted spindle morphology in tumor cells. Our studies further revealed that Nestin deficiency in U251 cells and GBM PDX cells repressed tumor growth upon transplantation. Finally, we found that Nestin deficiency sensitized GBM cells to microtubule-destabilizing drugs such as vinblastine and vincristine. Our studies demonstrate the essential functions and underlying mechanisms of Nestin in the growth and drug response of GBM cells. IMPLICATIONS: Through interaction with βII-tubulin, Nestin facilitates cell-cycle progression and spindle assembly of tumor cells in glioblastoma.

The plasticity of pancreatic cancer stem cells: implications in therapeutic resistance

The ever-growing perception of cancer stem cells (CSCs) as a plastic state rather than a hardwired defined entity has evolved our understanding of the functional and biological plasticity of these elusive components in malignancies. Pancreatic cancer (PC), based on its biological features and clinical evolution, is a prototypical example of a CSC-driven disease. Since the discovery of pancreatic CSCs (PCSCs) in 2007, evidence has unraveled their control over many facets of the natural history of PC, including primary tumor growth, metastatic progression, disease recurrence, and acquired drug resistance. Consequently, the current near-ubiquitous treatment regimens for PC using aggressive cytotoxic agents, aimed at ‘‘tumor debulking’’ rather than eradication of CSCs, have proven ineffective in providing clinically convincing improvements in patients with this dreadful disease. Herein, we review the key hallmarks as well as the intrinsic and extrinsic resistance mechanisms of CSCs that mediate treatment failure in PC and enlist the potential CSC-targeting ‘natural agents’ that are gaining popularity in recent years. A better understanding of the molecular and functional landscape of PCSC-intrinsic evasion of chemotherapeutic drugs offers a facile opportunity for treating PC, an intractable cancer with a grim prognosis and in dire need of effective therapeutic advances.

Involvement of Nestin in the Progression of Canine Mammary Carcinoma

Nestin, a class VI intermediate filament protein, is known to be expressed in various types of human neoplasms, including breast cancer, and is associated with their progression. However, its expression and role in canine mammary tumors remain unknown. We analyzed nestin expression in canine mammary tumors using in situ hybridization and immunohistochemistry. We also investigated its role in a canine mammary carcinoma cell line using RNA interference. Nestin expression was not observed in luminal epithelial cells of any of the 62 cases of benign mammary lesions examined, although myoepithelial cells showed its expression in most cases. In 16/50 (32%) primary mammary carcinomas and 6/15 (40%) metastases of mammary carcinomas, cytoplasmic nestin expression was detected in luminal epithelial cells. In luminal cells of primary mammary carcinomas, its expression was positively related to several pathological parameters that indicate high-grade malignancy, including histological grading (P < .01), vascular/lymphatic invasion (P < .01), Ki-67 index (P < .01), and metastasis (P < .05). Immunohistochemistry revealed that nestin expression was related to vimentin expression in mammary carcinomas (P < .01). This relationship was confirmed using reverse transcription-quantitative polymerase chain reaction using 9 cell lines derived from canine mammary carcinoma (P < .01). Finally, nestin knockdown in canine mammary carcinoma cells using small interfering RNA inhibited cell proliferation and migration based on WST-8, Boyden chamber, and cell-tracking assays. These findings suggest that nestin may at least partially mediate these behaviors of canine mammary carcinoma cells.

Cytoskeletal Dynamics in Epithelial-Mesenchymal Transition: Insights into Therapeutic Targets for Cancer Metastasis

In cancer cells, a vital cellular process during metastasis is the transformation of epithelial cells towards motile mesenchymal cells called the epithelial to mesenchymal transition (EMT). The cytoskeleton is an active network of three intracellular filaments: actin cytoskeleton, microtubules, and intermediate filaments. These filaments play a central role in the structural design and cell behavior and are necessary for EMT. During EMT, epithelial cells undergo a cellular transformation as manifested by cell elongation, migration, and invasion, coordinated by actin cytoskeleton reorganization. The actin cytoskeleton is an extremely dynamic structure, controlled by a balance of assembly and disassembly of actin filaments. Actin-binding proteins regulate the process of actin polymerization and depolymerization. Microtubule reorganization also plays an important role in cell migration and polarization. Intermediate filaments are rearranged, switching to a vimentin-rich network, and this protein is used as a marker for a mesenchymal cell. Hence, targeting EMT by regulating the activities of their key components may be a potential solution to metastasis. This review summarizes the research done on the physiological functions of the cytoskeleton, its role in the EMT process, and its effect on multidrug-resistant (MDR) cancer cells-highlight some future perspectives in cancer therapy by targeting cytoskeleton.

Game of Bones: How Myeloma Manipulates Its Microenvironment

Multiple myeloma is a clonal disease of long-lived plasma cells and is the second most common hematological cancer behind Non-Hodgkin’s Lymphoma. Malignant transformation of plasma cells imparts the ability to proliferate, causing harmful lesions in patients. In advanced stages myeloma cells become independent of their bone marrow microenvironment and form extramedullary disease. Plasma cells depend on a rich array of signals from neighboring cells within the bone marrow for survival which myeloma cells exploit for growth and proliferation. Recent evidence suggests, however, that both the myeloma cells and the microenvironment have undergone alterations as early as during precursor stages of the disease. There are no current therapies routinely used for treating myeloma in early stages, and while recent therapeutic efforts have improved patients’ median survival, most will eventually relapse. This is due to mutations in myeloma cells that not only allow them to utilize its bone marrow niche but also facilitate autocrine pro-survival signaling loops for further progression. This review will discuss the stages of myeloma cell progression and how myeloma cells progress within and outside of the bone marrow microenvironment.

Qualitative analysis of contribution of intracellular skeletal changes to cellular elasticity

Cells are dynamic structures that continually generate and sustain mechanical forces within their environments. Cells respond to mechanical forces by changing their shape, moving, and differentiating. These reactions are caused by intracellular skeletal changes, which induce changes in cellular mechanical properties such as stiffness, elasticity, viscoelasticity, and adhesiveness. Interdisciplinary research combining molecular biology with physics and mechanical engineering has been conducted to characterize cellular mechanical properties and understand the fundamental mechanisms of mechanotransduction. In this review, we focus on the role of cytoskeletal proteins in cellular mechanics. The specific role of each cytoskeletal protein, including actin, intermediate filaments, and microtubules, on cellular elasticity is summarized along with the effects of interactions between the fibers.

Optimized monoclonal antibody treatment against ELTD1 for GBM in a G55 xenograft mouse model

Glioblastoma is an aggressive brain tumour found in adults, and the therapeutic approaches available have not significantly increased patient survival. Recently, we discovered that ELTD1, an angiogenic biomarker, is highly expressed in human gliomas. Polyclonal anti-ELTD1 treatments were effective in glioma pre-clinical models, however, pAb binding is potentially promiscuous. Therefore, the aim of this study was to determine the effects of an optimized monoclonal anti-ELTD1 treatment in G55 xenograft glioma models. MRI was used to assess the effects of the treatments on animal survival, tumour volumes, perfusion rates and binding specificity. Immunohistochemistry and histology were conducted to confirm and characterize microvessel density and Notch1 levels, and to locate the molecular probes. RNA-sequencing was used to analyse the effects of the mAb treatment. Our monoclonal anti-ELTD1 treatment significantly increased animal survival, reduced tumour volumes, normalized the vasculature and showed higher binding specificity within the tumour compared with both control- and polyclonal-treated mice. Notch1 positivity staining and RNA-seq results suggested that ELTD1 has the ability to interact with and interrupt Notch1 signalling. Although little is known about ELTD1, particularly about its ligand and pathways, our data suggest that our monoclonal anti-ELTD1 antibody is a promising anti-angiogenic therapeutic in glioblastomas.

Expression Pattern of the Cancer Stem Cell Marker "Nestin" in Leukoplakia and Oral Squamous Cell Carcinoma

OBJECTIVE

The aim of the present study was to determine and compare the expression pattern and localization of nestin, in an attempt to explore its role in oral carcinogenesis.

METHODS

Western blot and immunohistochemistry analysis were performed to study the expression pattern of nestin in normal mucosa, leukoplakia, and oral squamous cell carcinoma samples. Nestin expression was evaluated in the keratinocytes and blood vessels of all the samples and compared with various clinico-pathological parameters.

RESULTS

Nestin expression was increased in samples of leukoplakia and oral squamous cell carcinoma when compared with normal mucosa. Among leukoplakia samples, the expression was increased in cases without dysplasia compared to cases with dysplastic features. In cases of oral squamous cell carcinoma, the expression of nestin was found to be decreased with the loss of differentiation. Neoangiogenesis status determined by nestin expression showed an increasing expression from normal mucosa through leukoplakia, to oral squamous cell carcinoma.

CONCLUSION

This study has two major findings: (1) identification of nestin as an effective indicator of neoangiogenesis, and (2) nestin may be used as a marker in predicting the early changes in oral carcinogenesis.

Quantitative Proteomics Links the Intermediate Filament Nestin to Resistance to Targeted BRAF Inhibition in Melanoma Cells

Targeted inhibition of mutated kinases using selective MAP kinase inhibitors in malignant melanoma often results in temporary improvement of clinical symptoms followed by rapid development of resistance. To gain insights in molecular processes that govern resistance, we performed SILAC-based quantitative proteomics profiling of vemurafenib-resistant and -sensitive melanoma cells. Among downregulated proteins in vemurafenib-resistant cell lines we detected multiple proteins involved in cytoskeletal organization and signaling, including the intermediate filament nestin, which was one of the most downregulated proteins. Previous studies showed that nestin is expressed in various types of solid tumors and its abundance correlates with malignant phenotype of transformed cells. However, the role of nestin in cancer cells regarding acquired resistance is still poorly understood. We performed CRISPR/Cas9 knockout of the nestin gene (NES) in vemurafenib-sensitive cells and showed that loss of nestin leads to increased cellular proliferation and colony formation upon treatment with BRAFV600E and MEK inhibitors. Moreover, nestin depletion led to increased invasiveness and metalloproteinase activity like the phenotype of melanoma cells with acquired resistance to the BRAF inhibitor. Finally, phosphoproteome analysis revealed that nestin depletion influenced signaling through integrin and PI3K/AKT/mTOR pathways and led to increased focal adhesion kinase abundance and phosphorylation. Taken together, our results reveal that nestin is associated with acquired vemurafenib resistance in melanoma cells.

The stem cell-specific intermediate filament nestin missense variation p.A1199P is associated with pancreatic cancer

The intermediate filament nestin is upregulated in stem/progenitor cells and cancers, and regulates cell proliferation, migration, invasion and stemness. The present study comparatively analyzed serial autopsies of Japanese patients (n=2,206; males, 1,225; females, 981; median, 80.7 years old; range, 33-104 years old) with malignant tumors of whole organs, with respect to the clinical information, and 5 single nucleotide polymorphisms of the nestin gene. p.A1199P associated with pancreatic cancer (odds ratio, 4.4; 95% confidence interval, 1.9-10.0, P=0.001) while it did not associate with malignant neoplasms in other organs. p.A1199P did not associate with precancerous lesions of the pancreas. Single nucleotide polymorphisms of nestin were not associated with sex, drinking, smoking, or body weight. In conclusion, the amino acid 1,199 of nestin is localized in the tail structure of the filament and polymerizes with other intermediate filament proteins. The present results suggest that missense variations of nestin affect pancreatic carcinogenesis in Japanese patients.

Dynamism, Sensitivity, and Consequences of Mesenchymal and Stem-Like Phenotype of Cancer Cells

There are remarkable similarities in the description of cancer stem cells (CSCs) and cancer cells with mesenchymal phenotype. Both cell types are highly tumorigenic, resistant against common anticancer treatment, and thought to cause metastatic growth. Moreover, cancer cells are able to switch between CSC and non-CSC phenotypes and vice versa, to ensure the necessary balance within the tumor. Likewise, cancer cells can switch between epithelial and mesenchymal phenotypes via well-described transition (EMT/MET) that is thought to be crucial for tumor propagation. In this review, we discuss whether, and to which extend, the CSCs and mesenchymal cancer cells are overlapping phenomena in terms of mechanisms, origin, and implication for cancer treatment. As well, we describe the dynamism of both phenotypes and involvement of the tumor microenvironment in CSC reversion and in EMT.

Pancreatic cancer stem cells: features and detection methods

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a high incidence of distant metastasis and recurrence. Cancer stem cells (CSCs), which are pluripotent, self-renewable, and capable of forming tumors, contribute to PDAC initiation and metastasis and are responsible for resistance to chemotherapy and radiation. Three types of experimental methods are commonly used to identify CSCs: CSC-specific marker detection, a sphere-formation assay that reveals cell proliferation under non-adherent conditions, and detection of side-population (SP) cells that possess high intracellular-to-extracellular pump functions. Several CSC-specific markers have been reported in PDACs, including CD133, CD24, CD44, CXCR4, EpCAM, ABCG2, c-Met, ALDH-1, and nestin. There remains controversy regarding which markers are specific to PDAC CSCs and which are expressed alone or in combination in CSCs. Examining characteristics of isolated CSCs and discovering CSC-specific treatment options are important to improve the prognosis of PDAC cases. This review summarizes CSC-detection methods for PDAC, including CSC-marker detection, the sphere-formation assay, and detection of SP cells.

Liver metastasis of pancreatic cancer: the hepatic microenvironment impacts differentiation and self-renewal capacity of pancreatic ductal epithelial cells

Pancreatic ductal adenocarcinoma (PDAC) is often diagnosed at advanced stages with the liver as the main site of metastases. The hepatic microenvironment has been shown to determine outgrowth of liver metastases. Cancer stem cells (CSCs) are essential for initiation and maintenance of tumors and acquisition of CSC-properties has been linked to Epithelial-Mesenchymal-Transition. Thus, this study aimed at elucidating whether and how the hepatic microenvironment impacts stemness and differentiation of disseminated pancreatic ductal epithelial cells (PDECs). Culture of premalignant H6c7-kras and malignant Panc1 PDECs together with hepatocytes and hepatic stellate cells (HSC) promoted self-renewal capacity of both PDEC lines. This was indicated by higher colony formation compared to cells cocultured with hepatocytes and hepatic myofibroblasts. Different Panc1 colony types derived from an HSC-enriched coculture were expanded and characterized revealing that holoclones exhibited an enhanced colony formation ability, elevated and exclusive expression of the CSC-marker Nestin and a more pronounced mesenchymal phenotype compared to paraclones. Moreover, Panc1 holoclone cells showed an increased tumorigenic potential in vivo leading to formation of undifferentiated tumors in 7/10 animals, while inoculation of paraclone cells only led to formation of tumors in 2/10 animals being smaller in number and size. Holoclone tumors were characterized by elevated expression of mesenchymal markers, complete loss of E-cadherin expression and high expression of Nestin. Finally, Etanercept-mediated TNF-α blocking partly reversed the mesenchymal CSC-phenotype of Panc1 holoclone cells. Overall, these data provide evidence that the hepatic microenvironment determines stemness and differentiation of PDECs, thereby substantially contributing to liver metastases of PDAC.

Implications of nestin in breast cancer pathogenesis (Review)

The aim of the present review was to summarize the current knowledge of the involvement of nestin in breast cancer (BC) pathogenesis. Nestin is a member of the class VI family of intermediate filament proteins, originally identified as a marker of neural stem cells and subsequently demonstrated to be expressed in BC and other cancer types. In normal breast tissue, nestin is expressed in the basal/myoepithelial cells of the mammary gland. In BC, nestin identifies basal-like tumours and predicts aggressive behaviour and poor prognosis. Nestin expression has also been detected in BC stem cells and newly-formed tumour vessels, being a factor in promoting invasion and metastasis. The present review provides an up-to-date overview of the involvement of nestin in processes facilitating BC pathogenesis and progression.

Reduced expression of the H19 long non-coding RNA inhibits pancreatic cancer metastasis

H19 is an oncofetal RNA expressed in the developing embryo as well as in bladder, breast, gastric, pancreatic, hepatocellular, and prostate cancers. Recent studies have shown that H19 enhances cancer invasion and metastasis; however, its roles in cancer remain controversial. In the current study, H19 exhibited the second largest increase (82.4-fold) and represented the only non-protein coding gene among 11 genes identified that were elevated over 10-fold in lung-metastasis-derived pancreatic cancer cells compared with their parental cells using a mouse metastatic model. Subsequently, we further clarified the roles of H19 in pancreatic cancer growth and metastasis using in vitro and in vivo techniques. In situ hybridization showed that H19 was detected in 23 of 139 invasive ductal carcinomas (17%), and that H19 expression positively correlated with higher histological grades (P < 0.0001). Overexpression of H19 in PANC-1 pancreatic cancer cells induced higher motilities, whereas H19 inhibition using shRNA and siRNA showed opposite results; however, cell growth rates were not impacted. Intravenous injection of H19 shRNA vector-transfected PANC-1 cells yielded marked inhibition of metastasis in the liver and lungs of immunodeficient mice. These findings suggest that H19 has important roles in pancreatic cancer metastasis, and that inhibition of H19 represents a novel candidate for pancreatic cancer therapy.

Emerging Role of Nestin as an Angiogenesis and Cancer Stem Cell Marker in Epithelial Ovarian Cancer: Immunohistochemical Study

Ovarian cancer is the most fatal gynecologic malignancy and the existing second-line treatments have not been confirmed to be effective. Cancer stem cells research has a leading role to explore promising therapeutic applications. Nestin was postulated to reflect cancer stem cell properties in various tumors, correlating with poor prognosis. Furthermore, nestin is proposed as a reliable neovascularization marker. This study aimed to elucidate the status of nestin expression in various epithelial ovarian cancers (EOCs), its neoangiogenic properties, and investigate its potential association with clinicopathologic parameters. A total of 80 primary EOCs (37 serous, 20 Mucinous, 13 endometrioid, and 10 clear cell carcinomas) were immunohistochemically stained with nestin. Staining intensity and automated microvascular density (MVD) were assessed. Positive nestin expression was defined in ≈47.5% of all EOC; more commonly in ≈60% of the serous tumors. It was noticeably expressed in tumor spheroids. Nestin expression significantly correlated with overall tumor grade, lymph node, distant metastasis, and stage. Nestin neoangiogenesis was detectable in all cases (average=60.1). The nestin expression in tumor cells significantly correlated with Nestin/MVD. The average Nestin/MVD was significantly an independent predictor of high tumor stage. As a stem cell marker, nestin is expressed in cells of EOC including those growing as spherules and correlated with poor prognosis. Thus, nestin may be a novel therapeutic target for tumor angiogenesis and a combination therapy that includes nestin-targeting agents may be an effective therapeutic approach. In addition, detection of Nestin/stem cells and Nestin/MVD can be used as predictors of disease.

Nestin suppression attenuates invasive potential of endometrial cancer cells by downregulating TGF-β signaling pathway

Nestin, an intermediate filament protein and a stem cell marker is expressed in several tumors. Until recently, little was known about the expression levels and the role of Nestin in endometrial cancer. Compared to the immortalized endometrial epithelial cell line EM-E6/E7-TERT, endometrial cancer cell lines express high to moderate levels of Nestin. Furthermore, endometrial tumors and tumor cell lines have a cancer stem-like cell subpopulation expressing CD133. Among the cancer lines, AN3CA and KLE cells exhibited both a significantly higher number of CD133+ cells and expressed Nestin at higher levels than Ishikawa cells. Knockdown of Nestin in AN3CA and KLE increased cells in G0/G1 phase of the cell cycle, whereas overexpression in Ishikawa decreased cells in G0/G1 phase and increased cells in S-phase. Nestin knockdown cells showed increased p21, p27, and PNCA levels and decreased expression of cyclin-D1 and D3. In contrast, Nestin overexpression revealed an inverse expression pattern of cell cycle regulatory proteins. Nestin knockdown inhibited cancer cell growth and invasive potential by downregulating TGF-β signaling components, MMP-2, MMP-9, vimentin, SNAIL, SLUG, Twist, N-cadherin, and upregulating the epithelial cell marker E-cadherin whereas the opposite was observed with Nestin overexpressing Ishikawa cells. Nestin knockdown also inhibited, while overexpression promoted invadopodia formation and pFAK expression. Knockdown of Nestin significantly reduced tumor volume in vivo. Finally, progesterone inhibited Nestin expression in endometrial cancer cells. These results suggest that Nestin can be a therapeutic target for cancer treatment.

Linking invasive motility to protein expression in single tumor cells

The invasion of malignant cells into tissue is a critical step in the progression of cancer. While it is increasingly appreciated that cells within a tumor differ in their invasive potential, it remains nearly unknown how these differences relate to cell-to-cell variations in protein expression. Here, we introduce a microfluidic platform that integrates measurements of invasive motility and protein expression for single cells, which we use to scrutinize human glioblastoma tumor-initiating cells (TICs). Our live-cell imaging microdevice is comprised of polyacrylamide microchannels that exhibit tissue-like stiffness and present chemokine gradients along each channel. Due to intrinsic differences in motility, cell subpopulations separate along the channel axis. The separated cells are then lysed in situ and each single-cell lysate is subjected to western blotting in the surrounding polyacrylamide matrix. We observe correlations between motility and Nestin and EphA2 expression. We identify protein-protein correlations within single TICs, which would be obscured with population-based assays. The integration of motility traits with single-cell protein analysis - on the same cell - offers a new means to identify druggable targets of invasive capacity.

RNAi-mediated human Nestin silence inhibits proliferation and migration of malignant melanoma cells by G1/S arrest via Akt-GSK3β-Rb pathway

Human Nestin (hNestin) has been found to express in melanoma, and its expression is positively correlated with the advanced stage of melanoma. However, the precise role of hNestin in the development of melanoma has not been fully understood. The present study aimed to explore the role of hNestin in the proliferation and invasion of melanoma cells. The lentivirus vector carrying a short hairpin RNAs (shRNAs) targeting hNestin (hNestin-shRNA-LV) was stably infected into human melanoma cells UACC903, which expressed high levels of hNestin. The effects of hNestin knockdown on the proliferation, apoptosis, migration of melanoma cells and the related signaling pathways were investigated by immunofluorence, Western blotting and reverse transcription polymerase chain reaction (RT-PCR), respectively. The results showed that hNestin was expressed in most melanoma specimens and the melanoma cells studied. Knockdown of hNestin expression significantly inhibited the proliferation of melanoma cells, blocked the formation of cell colony, arrested cell cycle at G₁/S stage and suppressed the activation of Akt and GSK3β. hNestin-silent cells also showed a sheet-like appearance with tight cell-cell adhesion, decreased membrane expression of N-cadherin and β-catenin, and attenuated migration. Furthermore, hNestin silence resulted in the inhibition of tumor growth in vivo. Our study indicates that hNestin knockdown suppresses the proliferation of melanoma cells, which might be through affecting Akt-GSK3β-Rb pathway-mediated G₁/S arrest, and hNestin silence inhibits the migration by selectively modulating the expression of cell adhesion molecules in the process of epithelial-mesenchymal transition.

Role of nestin expression in angiogenesis and breast cancer progression

Nestin is an intermediate filament protein and a stem cell marker expressed in several tumours. There is growing evidence of an association between the expression level of nestin and the pathogenesis of triple-negative breast cancer (TNBC). Nestin is also expressed in newly forming tumour vessels and is a valuable marker of ongoing angiogenesis. In this study, we aimed to evaluate the prognostic value of nestin expression in breast tumour cells and to determine whether this expression influences angiogenesis. Immunohistochemical (IHC) analyses were carried out on 124 cases of invasive ductal carcinoma (IDC) of the breast with a panel of murine monoclonal antibodies against nestin, CD31, CD34, SOX-18 and Ki‑67. We evaluated nestin expression in tumour and endothelial cells, Ki‑67 in tumour cells, and CD31, CD34 and SOX-18 in endothelial cells. Our results demonstrated that nestin expression in tumour cells correlated with the area and number of vessels expressing nestin, CD31, CD34 and SOX-18. We also found a positive correlation between nestin-expressing vessels and SOX-18-expressing vessels. Our results are consistent with those of previous studies, in which nestin expression in endothelial cells was shown to be strongly associated with triple-negative subtype, poorly differentiated G3 tumours, a higher proliferation index and a shorter overall survival. Nestin expression was also examined in human breast cancer cell lines (MCF-7, SK-BR-3, MDA‑MB‑231 and BO2 cells) representing a different level of tumour aggressiveness and reflecting histological grade. A higher nestin protein level was observed in more aggressive MDA‑MB‑231 and BO2 cells than in MCF-7 and SK-BR-3 cells.

FL118, a novel survivin inhibitor, wins the battle against drug-resistant and metastatic lung cancers through inhibition of cancer stem cell-like properties

Failure of cancer treatment caused by drug resistance and metastasis is mainly due to existence of cancer stem cells (CSCs). Therefore, targeting CSCs to overcome cancers is a challenging issue in clinic. In this report, in view of the important role of survivin in tumor growth and CSCs maintaining, we aimed to confirm that FL118, as a novel survivin inhibitor, may effectively inhibit lung cancer stem cells. We showed that lung cancer stem cells have the obviously higher expression of survivin than their parental cells. After treated with FL118, the survivin level in CSCs was suppressed. Consistently, lung cancer stem cells displayed significantly growth inhibition over time. Here, we compared the antitumor efficacy between FL118 and cisplatin. The data revealed that CSCs are more sensitive to FL118 than cisplatin. To further demonstrate the inhibitory effect of FL118 on CSCs, we found that FL118 down-regulated the expression of CSCs markers (ABCG2, ALDH1A1, Oct4) and drug resistant proteins (P-gp, ERCC1), suggesting that FL118 may change CSCs phenotype and improve drug-sensitivity of tumor cells. Moreover, FL118 effectively decreased the invasive ability of CSCs. These findings expand the uniqueness of FL118 as an attractive therapeutic option for cancers with drug-resistant or metastatic potential.

Pancreatic neuroendocrine carcinoma with exocrine differentiation in a young cat

A 35-mo-old spayed female mixed-breed cat with continuous vomiting, emaciation, and abdominal distention for 2 wk was presented to a private veterinary clinic for evaluation. At 71 d after the initial visit, the cat died with anemia, jaundice, and hypoalbuminemia, and was subjected to autopsy. Grossly, numerous firm masses, 0.5-2.5 cm diameter, were randomly located in the left lobe of the pancreas. Histologic examination revealed that the pancreatic mass consisted of 2 tumor cell types: mostly small round cells with a minority of epithelial cells. The small cells were arranged in nests of various sizes, which were separated by thin fibrous stroma, and had small, round, hyperchromatic nuclei, scant cytoplasm containing argyrophilic granules, and often formed rosettes. The epithelial cells formed luminal structures. Metastases were observed in the liver, greater omentum, and pancreatic, gastric, pulmonary, and mediastinal lymph nodes. Immunohistochemical examination revealed that the small cells were positive for vimentin, neuron-specific enolase, chromogranin A, cytokeratin (CK) AE1/AE3, and trypsin, whereas the epithelial cells were positive for AE1/AE3, trypsin, CK19, and nestin. Ultrastructurally, the small cells contained abundant electron-dense granules, ~200 nm diameter, whereas the epithelial cells had apical microvilli and numerous zymogen granules, ~300 nm diameter. These findings indicated that the tumor was a pancreatic neuroendocrine carcinoma with exocrine differentiation and systemic metastases.

Nestin phosphorylation at threonines 315 and 1299 correlates with proliferation and metastasis of human pancreatic cancer

The neuroepithelial stem cell marker nestin is a cytoskeletal protein that regulates cell proliferation, invasion, and stemness in various tumors, including pancreatic tumors. In the present study, we examined the expression and roles of phosphorylated nestin in pancreatic cancer cells. Nestin phosphorylation at threonines 315 (Thr315) and 1299 (Thr1299) was observed during mitosis in human pancreatic cancer cells. Nestin phosphorylation was positively correlated with a cell proliferation marker, MIB-1 expression in human pancreatic cancer samples. Transfection of MIA PaCa-2 cells with nestin mutated at Thr315 and/or Thr1299 (to suppress phosphorylation) resulted in lower proliferation rates than those in control groups. Transfecting MIA PaCa-2 cells with wild-type nestin or with nestin mutated at Thr315 increased migration and invasion. In contrast, transfection with nestin mutated at both phosphorylation sites (Thr315 and Thr1299) did not enhance cell migration or invasion. In an intra-splenic xenograft experiment using MIA PaCa-2 cells, tumors expressing the nestin double mutant formed fewer liver metastases than tumors expressing wild-type nestin. Nestin phosphorylation at these two sites was decreased upon treatment with inhibitors for cyclin dependent kinases, AKT, and Aurora in PANC-1 cells, which express a high baseline level of phosphorylated nestin. These findings suggest that phosphorylation of nestin at Thr315 and/or Thr1299 affects cell proliferation, and inhibition of both phosphorylation sites suppresses invasion and metastasis of human pancreatic cancer. Inhibiting nestin phosphorylation at these two sites may represent a novel therapeutic strategy for pancreatic cancer.

Establishment and characterization of a new human acinar cell carcinoma cell line, Faraz-ICR, from pancreas

OBJECTIVES

Basic research in the field of acinar cell carcinoma (ACC) as a rare neoplasm of the pancreas is dependent on the availability of pragmatic model such as new pancreatic cancer cell lines. Thus, establishment and characterization of new pancreatic cancer cell lines from ACC origin are deemed important.

METHODS

Faraz-ICR cell line was derived from a 58-years old woman with pancreatic acinar cell carcinoma by the collagenase digestion protocol. We characterized the cell line by examining its morphology and cytostructural and functional profile.

RESULTS

Faraz-ICR has a doubling time of 35 hours and grows in soft agar with a colony-forming efficiency of 25%. The cell had nearly normal pattern of chromosomes in karyotype analysis and Comparative Genomic Hybridization (CGH) array analysis. Evaluation of cells by flowcytometry showed that Faraz-ICR is negative for EpCAM and mesenchymal markers in different passages, and has epithelial nature. Immunofluorescence staining revealed that cells were strongly positive for vimentin, desmin, ezrin, S100, nestin and they were negative for pan-cytokeratins, chromogranin and alpha smooth muscle actin.

CONCLUSIONS

We were able to establish a new pancreatic carcinoma cell line with partial aspects of Epithelial-mesenchymal transition and aggressiveness. This cell line might be suitable for studying various anticancer drugs and protein profile aiming to see any possible tumor associated marker for ACC.

The role of cancer stem cells in tumor heterogeneity and resistance to therapy

Cancer is a heterogenous disease displaying marked inter- and intra-tumoral diversity. The existence of cancer stem cells (CSCs) has been experimentally demonstrated in a number of cancer types as a subpopulation of tumor cells that drives the tumorigenic and metastatic properties of the entire cancer. Thus, eradication of the CSC population is critical for the complete ablation of a tumor. This is, however, confounded by the inherent resistance of CSCs to standard anticancer therapies, eventually leading to the outgrowth of resistant tumor cells and relapse in patients. The cellular mechanisms of therapy resistance in CSCs are ascribed to several factors including a state of quiescence, an enhanced DNA damage response and active repair mechanisms, up-regulated expression of drug efflux transporters, as well as the activation of pro-survival signaling pathways and inactivation of apoptotic signaling. Understanding the mechanisms underlying the acquisition of resistance to therapy may hold the key to targeting the CSC population.

High efficiency penetration of antibody-immobilized nanoneedle thorough plasma membrane for in situ detection of cytoskeletal proteins in living cells

Background

The field of structural dynamics of cytoskeletons in living cells is gathering wide interest, since better understanding of cytoskeleton intracellular organization will provide us with not only insights into basic cell biology but may also enable development of new strategies in regenerative medicine and cancer therapy, fields in which cytoskeleton-dependent dynamics play a pivotal role. The nanoneedle technology is a powerful tool allowing for intracellular investigations, as it can be directly inserted into live cells by penetrating through the plasma membrane causing minimal damage to cells, under the precise manipulation using atomic force microscope. Modifications of the nanoneedles using antibodies have allowed for accurate mechanical detection of various cytoskeletal components, including actin, microtubules and intermediate filaments. However, successful penetration of the nanoneedle through the plasma membrane has been shown to vary greatly between different cell types and conditions. In an effort to overcome this problem and improve the success rate of nanoneedle insertion into the live cells, we have focused here on the fluidity of the membrane lipid bilayer, which may hinder nanoneedle penetration into the cytosolic environment.

Results

We aimed to reduce apparent fluidity of the membrane by either increasing the approach velocity or reducing experimental temperatures. Although changes in approach velocity did not have much effect, lowering the temperature was found to greatly improve the detection of unbinding forces, suggesting that alteration in the plasma membrane fluidity led to increase in nanoneedle penetration.

Conclusions

Operation at a lower temperature of 4 °C greatly improved the success rate of nanoneedle insertion to live cells at an optimized approach velocity, while it did not affect the binding of antibodies immobilized on the nanoneedle to vimentins for mechanical detection. As these experimental parameters can be applied to various cell types, these results may improve the versatility of the nanoneedle technology to other cell lines and platforms.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-016-0226-5) contains supplementary material, which is available to authorized users.

Cancer stem cells and epithelial-mesenchymal transition: Novel therapeutic targets for cancer

Despite the development of various therapeutic approaches, recurrence and metastasis remain major problems for patients with advanced cancer. Recent studies have shown that cancer stem cells (CSCs) play an important role in cancer aggressiveness. In cancer tissues, a small number of CSCs are able to self-renew and differentiate into heterogeneous cancer cells. CSCs usually remain in the resting phase of the cell cycle and possess efficient drug efflux pathways. Thus, they are resistant to chemoradiotherapy and surviving CSCs contribute to recurrence. During cancer metastasis, CSCs undergo epithelial-mesenchymal transition (EMT), thereby acquiring mesenchymal features, migrating to adjacent stromal tissues, and invading blood or lymph vessels. Recent studies showed that EMT-inducible factors also enhance or induce CSC-like features in cancer cells. These findings suggest that EMT is closely correlated with cancer recurrence and metastasis. Inhibition of nestin, a CSC marker, reduces the aggressiveness of several types of cancer. Suppression of the mesenchymal variant of fibroblast growth factor (FGFR)-2, FGFR-2 IIIc, and regulation of the EMT using epithelial splicing regulatory protein 1 (ESRP1) are effective in the treatment of immunodeficient mice with pancreatic cancer. The roles of CSCs and EMT in cancer and possible therapies are discussed in this review.

Nestin regulates neural stem cell migration via controlling the cell contractility

Neural stem cells (NSCs) migration is essential for neurogenesis and neuroregeneration after brain injury. Nestin, a widely used marker of NSCs, is expressed abundantly in several cancers, where it may correlate with tumor migration and invasion. However, it is not yet known whether nestin participates in NSC migration. Here, we show that nestin down-regulation significantly inhibits the migration and contraction of murine neural stem cells, but does not obviously influence the proliferation, filamentous actin (F-actin) content, distribution or focal adhesion assembly of these cells. Mechanistically, nestin knockdown was found to affect the phosphorylation state of myosin regulatory light chain (MRLC) and regulate the activity of myosin light chain kinase (MLCK). Co-immunoprecipitation experiments showed that it interacts with MLCK and MRLC. Together, our results indicate that nestin may increase NSC motility via elevating MLCK activity through direct binding and provide new insight into the roles of nestin in NSC migration and repair.

Systemic Administration of Small Interfering RNA Targeting Human Nestin Inhibits Pancreatic Cancer Cell Proliferation and Metastasis

OBJECTIVES

Nestin, a progenitor/stem cell marker, is expressed in human pancreatic cancer, where its expression correlates positively with invasiveness and metastasis. Here, we investigated the inhibition of nestin expression and the regulation of nestin expression.

METHODS

We analyzed the effects of small interfering RNA (siRNA) targeting nestin using pancreatic cancer cell lines.

RESULTS

Nestin siRNA inhibited the growth, migration, invasion, and sphere-forming ability of the pancreatic cancer cell lines. Pancreatic cancer cells cotreated with gemcitabine and nestin siRNA exhibited lower cell viability than cells treated with a control siRNA, gemcitabine alone, or nestin siRNA alone. Cells derived from the metastatic nodules of mice showed higher nestin expression than the parental cells, and nestin expression in pancreatic cancer cells was regulated by methylation of the nestin gene. In an orthotopic implantation model using mice, administration of nestin siRNA significantly decreased primary and metastatic tumor formation by human pancreatic cancer cells compared to tumor formation in control siRNA-treated mice.

CONCLUSIONS

Nestin plays a key role in pancreatic cancer cell metastasis and stemness and that administration of nestin siRNA may offer a novel therapeutic strategy for pancreatic cancer.

Nestin: A biomarker of aggressive uterine cancers

OBJECTIVE

Evidence of potential prognostic and predictive value for nestin was investigated in well-annotated uterine cancers (UCs).

METHODS

Nestin expression and previously-published biomarkers were evaluated by immunohistochemistry (IHC) in UC tissue microarrays. Biomarkers were categorized as low vs. high, and nestin was cut at 10% positive staining. Relationship between nestin and clinicopathologic factors, biomarkers and outcome were evaluated using exact/log-rank testing or logistic/Cox modeling.

RESULTS

There were 323 eligible cases, 34% had advanced stage disease, 37% had type II disease, and 5% were carcinosarcomas. High nestin, observed in 19% of cases, was more common in advanced vs. early stage disease, type II cancers or uterine carcinosarcoma vs. type I cancers, grade 3 disease, positive lymphovascular space invasion (LVSI) and tumors >6cm (p<0.05). Nestin was inversely correlated with ER, PR and TFF3, and correlated with p53 and IMP3. Women with high vs. low nestin had worse progression-free survival (PFS) and cancer-specific survival overall, and worse PFS in the subset who received no adjuvant therapy or radiation, or had early stage, type I disease or tumors with both low and high ER, PR, TFF3, PTEN, p53 or IMP3. The relationship between nestin and PFS was independent of stage, LVSI and risk categorization but not type of UC.

CONCLUSIONS

High nestin was more common in UCs with aggressive features and poor outcome. Nestin may represent a predictive biomarker for treatment selection for patients previously considered to be lower risk and a candidate for no or radiation-based adjuvant therapy, and compliment ER/PR testing.

Studying Nestin and its Interrelationship with Cdk5

Current research utilizes the specific expression pattern of intermediate filaments (IF) for identifying cellular state and origin, as well as for the purpose of disease diagnosis. Nestin is commonly utilized as a specific marker and driver for CNS progenitor cell types, but in addition, nestin can be found in several mesenchymal progenitor cells, and it is constitutively expressed in a few restricted locations, such as muscle neuromuscular junctions and kidney podocytes. Alike most other members of the IF protein family, nestin filaments are dynamic, constantly being remodeled through posttranslational modifications, which alter the solubility, protein levels, and signaling capacity of the nestin filaments. Through its interactions with kinases and other signaling executors, resulting in a complex and bidirectional regulation of cell signaling events, nestin has the potential to determine whether cells divide, differentiate, migrate, or stay in place. In this review, the broad and similar roles of IFs as dynamic signaling scaffolds, is exemplified by observations of nestin functions and its interaction with the cyclin- dependent kinase 5, the atypical kinase in the family of cyclin-dependent kinases.

Nestin regulates proliferation and invasion of gastrointestinal stromal tumor cells by altering mitochondrial dynamics

Nestin is widely expressed in numerous tumors and has become a diagnostic and prognostic indicator. However, the exact mechanism by which nestin contributes to tumor malignancy remains poorly understood. Here, we found marked upregulation of nestin expression in highly proliferative and invasive gastrointestinal stromal tumor (GIST) specimens. Nestin knockdown in GIST cells reduced the proliferative and invasive activity owing to a decrease of mitochondrial intracellular reactive oxygen species (ROS) generation. Furthermore, nestin was co-localized with mitochondria, and knockdown of nestin increased mitochondrial elongation and influenced the mitochondrial function, including oxygen consumption rates, ATP generation and mitochondrial membrane potential and so on. In exploring the underlying mechanism, we demonstrated nestin knockdown inhibited the mitochondrial recruitment of Dynamin-related protein1 and induced the change of mitochondrial dynamics. Thus, nestin may have an important role in GIST malignancy by regulating mitochondrial dynamics and altering intracellular ROS levels. The findings provide new clues to reveal mechanisms by which nestin mediates the proliferation and invasion of GISTs.

Global Analysis of Protein Expression and Phosphorylation Levels in Nicotine-Treated Pancreatic Stellate Cells

Smoking is a risk factor in pancreatic disease; however, the biochemical mechanisms correlating smoking with pancreatic dysfunction remain poorly understood. Strategies using multiplexed isobaric tag-based mass spectrometry facilitate the study of drug-induced perturbations on biological systems. Here, we present the first large-scale analysis of the proteomic and phosphoproteomic alterations in pancreatic stellate cells following treatment with two nicotinic acetylcholine receptor (nAChR) ligands: nicotine and α-bungarotoxin. We treated cells with nicotine or α-bungarotoxin for 12 h in triplicate and compared alterations in protein expression and phosphorylation levels to mock-treated cells using a tandem mass tag (TMT9plex)-based approach. Over 8100 proteins were quantified across all nine samples, of which 46 were altered in abundance upon treatment with nicotine. Proteins with increased abundance included those associated with neurons, defense mechanisms, indicators of pancreatic disease, and lysosomal proteins. In addition, we measured differences for ∼16 000 phosphorylation sites across all nine samples using a titanium dioxide-based strategy, of which 132 sites were altered with nicotine and 451 with α-bungarotoxin treatment. Many altered phosphorylation sites were involved in nuclear function and transcriptional events. This study supports the development of future targeted investigations to establish a better understanding for the role of nicotine and associated receptors in pancreatic disease.

Role of cellular cytoskeleton in epithelial-mesenchymal transition process during cancer progression

Currently, cancer metastases remain a major clinical problem that highlights the importance of recognition of the metastatic process in cancer diagnosis and treatment. A critical process associated with the metastasis process is the transformation of epithelial cells toward the motile mesenchymal state, a process called epithelial-mesenchymal transition (EMT). Increasing evidence suggests the crucial role of the cytoskeleton in the EMT process. The cytoskeleton is composed of the actin cytoskeleton, the microtubule network and the intermediate filaments that provide structural design and mechanical strength that is necessary for the EMT. The dynamic reorganization of the actin cytoskeleton is a prerequisite for the morphology, migration and invasion of cancer cells. The microtubule network is the cytoskeleton that provides the driving force during cell migration. Intermediate filaments are significantly rearranged, typically switching from cytokeratin-rich to vimentin-rich networks during the EMT process, accompanied by a greatly enhanced cell motility capacity. In the present review, the recent novel insights into the different cytoskeleton underlying EMT are summarized. There are numerous advances in our understanding of the fundamental role of the cytoskeleton in cancer cell invasion and migration.

Nestin expression as an independent indicator of poor prognosis for patients with anaplastic thyroid cancer

The protein nestin, a neuronal stem cell marker, has been reported to indicate a poor prognosis in various tumours. Anaplastic thyroid cancer (ATC) is one of the most aggressive malignancies in humans, and its molecular background has not been identified. The present study evaluated the expression of nestin and its significance in ATC. Tissue samples from 23 patients with ATC were subjected to immunohistochemical staining and the staining intensity of nestin in the cytoplasm was evaluated. The expression of nestin in the tumour cytoplasm was confirmed in 6 of the 23 tissue samples (26.1%). Between the nestin-positive group (n=6) and the nestin-negative group (n=17), there were no significant differences in the clinicopathological factors of the patients. However, the nestin-positive group exhibited significantly worse prognoses than the nestin-negative group (median survival time, 86.5 vs. 306 days; P<0.01, log-rank test). The multivariate analysis indicated that nestin expression was a prognostic indicator for the ATC patients (hazard ratio, 5.59; 95% confidence interval, 1.63-19.50; P<0.01), which is independent of the known clinical indicators. Nestin expression has the potential to be an independent indicator of a poor prognosis for patients with ATC.

Fixation methods for the preservation of morphology, RNAs, and proteins in paraffin-embedded human cervical cancer cell xenografts in mice

After various types of fixation, paraffin-embedded tissues are commonly used for histological analysis and pathological diagnosis; they are also suitable for long-term storage. Neutral buffered formalin, paraformaldehyde, and ethanol are common fixatives for histopathological analysis. For molecular biological analysis, fixed paraffin-embedded tissues are valuable resources; suitable fixative solutions and methods are needed to quantify and perform molecular biological analyses including immunohistochemistry, in situ hybridization, and quantitative polymerase chain reaction. Currently, 4 % paraformaldehyde is the recommended fixative for the preservation of RNAs and proteins, as well as for morphological study in paraffin-embedded human cervical cancer tissues that were xenografted in immunodeficient mice. Here, we describe the method for the fixation and preparation of paraffin-embedded tissue specimens for analysis of RNAs, proteins, and morphology.

Nestin depletion induces melanoma matrix metalloproteinases and invasion

Matrix metalloproteinases (MMPs) are key biological mediators of processes as diverse as wound healing, embryogenesis, and cancer progression. Although MMPs may be induced through multiple signaling pathways, the precise mechanisms for their regulation in cancer are incompletely understood. Because cytoskeletal changes are known to accompany MMP expression, we sought to examine the potential role of the poorly understood cytoskeletal protein, nestin, in modulating melanoma MMPs. Nestin knockdown (KD) upregulated the expression of specific MMPs and MMP-dependent invasion both through extracellular matrix barriers in vitro and in peritumoral connective tissue of xenografts in vivo. The development of three-dimensional melanospheres that in vitro partially recapitulate noninvasive tumorigenic melanoma growth was inhibited by nestin KD, although ECM invasion by aberrant melanospheres that did form was enhanced. Mechanistically, nestin KD-dependent melanoma invasion was associated with intracellular redistribution of phosphorylated focal adhesion kinase and increased melanoma cell responsiveness to transforming growth factor-beta, both implicated in pathways of melanoma invasion. The results suggest that the heretofore poorly understood intermediate filament, nestin, may serve as a novel mediator of MMPs critical to melanoma virulence.

Inhibition of fibroblast growth factor receptor 2 attenuates proliferation and invasion of pancreatic cancer

The alternative splicing of the extracellular domain of fibroblast growth factor receptor (FGFR)-2 generates the IIIb and IIIc isoforms. Expression of FGFR-2 IIIb correlates with vascular endothelial growth factor-A (VEGF-A) expression and venous invasion of pancreatic ductal adenocarcinoma (PDAC). By contrast, FGFR-2 IIIc expression correlates with faster development of liver metastasis after surgery, and increased proliferation rates and invasion of the cancer. In this study, we analyzed the expression and roles of total FGFR-2 (both isoforms) to determine the effectiveness of FGFR-2-targeting therapy for PDAC. Immunohistochemically, FGFR-2 was highly expressed in 25/48 (52.1%) PDAC cases, and correlated with advanced stage cancer. In FISH analysis, FGFR2 was amplified in 3/7 PDAC cell lines. We stably transfected an FGFR-2 shRNA targeting the IIIb and IIIc isoforms into FGFR2-amplified PDAC cells. The proliferation rates, migration, and invasion of FGFR-2-shRNA-transfected cells were lower than those of control cells in vitro. In response to FGF-2, FGFR-2-shRNA-transfected cells showed decreased phosphorylation of ERK compared with control cells. The FGFR-2-shRNA-transfected cells also expressed lower levels of vascular endothelial growth factor-A than control cells, and formed smaller s.c. tumors in nude mice. These findings suggest that FGFR-2 is a therapeutic target for inhibition in PDAC.

Nestin involvement in tissue injury and cancer--a potential tumor marker?

BACKGROUND

In eukaryotic cells, the cytoskeleton contains three major filamentous components: actin microfilaments, microtubules and intermediate filaments. Nestin represents one of the class VI intermediate filament proteins. Clinical and molecular analyses have revealed substantial information regarding the presence of Nestin in cells with progenitor or stem cell properties. During tissue injury Nestin is expressed in cells with progenitor cell-like properties. These cells may serve as a tissue reserve and, as such, may contribute to tissue repair. Based on currently available data, Nestin also appears to be implicated in two oncogenic processes. First, Nestin has been found to be expressed in cancer stem-like cells and poorly differentiated cancer cells and, as such, Nestin is thought to contribute to the aggressive behavior of these cells. Second, Nestin has been found to be involved in tumor angiogenesis through an interaction of cancer cells and blood vessel endothelial cells and, as such, Nestin is thought to facilitate tumor growth.

CONCLUSIONS

We conclude that Nestin may serve as a promising tumor marker and as a potential therapeutic target amenable to tumor suppression and angiogenesis inhibition.

Establishment of highly tumorigenic human colorectal cancer cell line (CR4) with properties of putative cancer stem cells

Background

Colorectal cancer (CRC) has the third highest mortality rates among the US population. According to the most recent concept of carcinogenesis, human tumors are organized hierarchically, and the top of it is occupied by malignant stem cells (cancer stem cells, CSCs, or cancer-initiating cells, CICs), which possess unlimited self-renewal and tumor-initiating capacities and high resistance to conventional therapies. To reflect the complexity and diversity of human tumors and to provide clinically and physiologically relevant cancer models, large banks of characterized patient-derived low-passage cell lines, and especially CIC-enriched cell lines, are urgently needed.

Principal Findings

Here we report the establishment of a novel CIC-enriched, highly tumorigenic and clonogenic colon cancer cell line, CR4, derived from liver metastasis. This stable cell line was established by combining 3D culturing and 2D culturing in stem cell media, subcloning of cells with particular morphology, co-culture with carcinoma associated fibroblasts (CAFs) and serial transplantation to NOD/SCID mice. Using RNA-Seq complete transcriptome profiling of the tumorigenic fraction of the CR4 cells in comparison to the bulk tumor cells, we have identified about 360 differentially expressed transcripts, many of which represent stemness, pluripotency and resistance to treatment. Majority of the established CR4 cells express common markers of stemness, including CD133, CD44, CD166, EpCAM, CD24 and Lgr5. Using immunocytochemical, FACS and western blot analyses, we have shown that a significant ratio of the CR4 cells express key markers of pluripotency markers, including Sox-2, Oct3/4 and c-Myc. Constitutive overactivation of ABC transporters and NF-kB and absence of tumor suppressors p53 and p21 may partially explain exceptional drug resistance of the CR4 cells.

Conclusions

The highly tumorigenic and clonogenic CIC-enriched CR4 cell line may provide an important new tool to support the discovery of novel diagnostic and/or prognostic biomarkers as well as the development of more effective therapeutic strategies.