Later Stages Of Tumor Progression Research Articles

Short SULF1/SULF2 splice variants predominate in mammary tumours with a potential to facilitate receptor tyrosine kinase-mediated cell signalling.

The relative roles of SULF1 and SULF2 enzymes in tumour growth are controversial, but short SULF1/SULF2 splice variants predominate in human mammary tumours despite their non-detectable levels in normal mammary tissue. Compared with the normal, the level of receptor tyrosine kinase (RTK) activity was markedly increased in triple-positive mammary tumours during later stages of tumour progression showing increased p-EGFR, p-FGFR1 and p-cMet activity in triple-positive but not in triple-negative tumours. The abundance of catalytically inactive short SULF1/SULF2 variants permits high levels of HS sulphation and thus growth driving RTK cell signalling in primary mammary tumours. Also observed in this study, however, was increased N-sulphation detected by antibody 10E4 indicating that not only 6-O sulphation but also N-sulphation may contribute to increased RTK cell signalling in mammary tumours. The levels of such increases in not only SULF1/SULF2 but also in pEGFR, pFGFR1, p-cMet and Smad1/5/8 signalling were further enhanced following lymph node metastasis. The over-expression of Sulf1 and Sulf2 variants in mammary tumour-derived MDA-MB231 and MCF7 cell lines by transfection further confirms Sulf1-/Sulf2-mediated differential modulation of growth. The short variants of both Sulf1 and Sulf2 promoted FGF2-induced MDA-MB231 and MCF7 in vitro growth while full-length Sulf1 inhibited growth supporting in vivo mammary tumour cell signalling patterns of growth. Since a number of mammary tumours become drug resistant to hormonal therapy, Sulf1/Sulf2 inhibition could be an alternative therapeutic approach to target such tumours by down-regulating RTK-mediated cell signalling.

Targeting vasculogenesis to prevent progression in multiple myeloma.

The role of endothelial progenitor cell (EPC)-mediated vasculogenesis in hematological malignancies is not well explored. Here, we showed that EPCs are mobilized from the bone marrow (BM) to the peripheral blood at early stages of multiple myeloma (MM); and recruited to MM cell-colonized BM niches. Using EPC-defective ID1+/- ID3-/- mice, we found that MM tumor progression is dependent on EPC trafficking. By performing RNA-sequencing studies, we confirmed that endothelial cells can enhance proliferation and favor cell-cycle progression only in MM clones that are smoldering-like and have dependency on endothelial cells for tumor growth. We further confirmed that angiogenic dependency occurs early and not late during tumor progression in MM. By using a VEGFR2 antibody with anti-vasculogenic activity, we demonstrated that early targeting of EPCs delays tumor progression, while using the same agent at late stages of tumor progression is ineffective. Thus, although there is significant angiogenesis in myeloma, the dependency of the tumor cells on EPCs and vasculogenesis may actually precede this step. Manipulating vasculogenesis at an early stage of disease may be examined in clinical trials in patients with smoldering MM, and other hematological malignancies with precursor conditions.

Immune cell responses to combined treatment of murine melanoma with ALT-803 and Sunitinib in normal and chronic alcohol consuming mice (TUM2P.1032)

Abstract The immune enhancing IL-15 super agonist ALT-803 and Sunitinib, a tyrosine kinase inhibitor that inhibits immunosuppressive myeloid derived suppressor cells (MDSC) and T regulatory (Treg) cells, were examined for their single and combined effects on immune cell phenotype in normal and chronic alcohol consuming (CAC) mice inoculated with s.c. B16BL6 melanoma. ALT-803 alone and in combination with Sunitinib initially increased CD8+CD44hi and CD8+CD44hiCD62Llo memory phenotype T cells in the spleen and PBL. IFN-γ producing CD8+CD44hi T cells increased in the spleen and the increase was more robust in CAC versus normal mice. These responses decayed during the later stages of tumor growth, and declined more rapidly in the CAC mice. Sunitinib alone did not affect CD8+ T cells or their IFN-γ production. Sunitinib alone and in combination with ALT-803 prevented the increase in CD11b+Gr-1int MDSC in the spleen associated with no treatment or ALT-803 treatment in normal mice; however, the effect was less pronounced in CAC mice where MDSC did not increase in the untreated group over time. MDSC in the PBL increased over time in untreated and ALT-803-treated normal mice. Sunitinib prevented this increase until the late stages of tumor progression. Sunitinib alone and in combination suppressed CD4+CD25+FoxP3+ Treg cells in the spleen during tumor progression.

Abstract A09: Single-cell RNA sequencing reveals phenotypic plasticity of drug tolerant, clonal populations of cancer cells

Abstract Cancer recurrence and metastatic tumors might arise not only from residual primary tumor cells but even from precancerous cells that are able to spread and seed distant organs. Thus, residual pre-neoplastic and neoplastic cells that persist following treatment constitute an ideal evolutionary niche for cancer evolution. We have investigated the role of the TGF-beta; signaling pathway, which is widely known as a pro-metastatic in late stages of tumor progression, in the context of the cellular response to genotoxic stress induced by chemotherapy drugs. We identified that TGF-beta signaling contribute to drug resistance by repressing the DNA damage response through a coordinate repression of transcription and translation of p53 and the stress response in precancerous and cancer cells. Indeed, TGF-beta/Smad signaling enacts an intrinsic survival pathway in metastatic cancer cells. However, the molecular events accompanying the evolution towards a drug tolerant phenotype are not well understood. Indeed, severe cellular stress might generate or select a subpopulation of reversibly stress-tolerant cells under conditions that are lethal to the majority of the population. Thus, drug tolerance could be attributed to heterogeneity of gene expression within the population to ensure survival of a minority under stress. To address these questions, we developed an experimental paradigm to generate and propagate populations of paclitaxel tolerant precancerous (MCF10A) and metastatic cancer (MDA-MB-231) cells that can resume proliferation after 1 week of consecutive treatment with lethal doses of the drug. We found that drug-tolerant cells reacquired Paclitaxel-sensitivity after expansion. Then we performed whole transcriptome sequencing to identify single nucleotide variants (SNVs) and gene expression profiles at the single-cell level associated with the evolution towards a reversible drug tolerant state in cancer cells. We evaluated untreated, stress-arrested and proliferating drug-tolerant cells from a small (n<64) clonal population. In addition to sequencing the mRNA of single cells, we also performed DNA and RNA sequencing of populations of untreated and drug-tolerant cells to aid in the identification of RNA variants. We performed differential gene expression profiling for single cells and population cells of the three groups to identify the transcriptional stress response and cytotoxic effects of Paclitaxel on gene expression. We find that within untreated, stress-arrested and drug-tolerant cell groups, specific transcriptional programs were enacted while generating high heterogeneity between single cells within and between groups. Drug-tolerant cells contained specific RNA variants encoded by genes involved in microtubule organization and stabilization as well as cell adhesion and cell surface signaling. Unexpectedly, Drug-tolerant cells from a single progenitor cell rapidly reacquired high degree of heterogeneity in gene expression similar to untreated cells, within a few doublings, while uniquely expressing SNVs and genes such as Integrin alpha 6, the histone demethylase KDM5A, and the IGF-1 receptor. Interestingly, despite of the high degree of heterogeneity, the whole gene expression profiles, of each cell rather than small gene sets can identify the response of cells to taxol. Thus, single cell analyses reveal the dynamics of the response to stress in terms of cell-specific SNVs driving heterogeneity, the survival of a minority population through generation of specific genes and RNA variants and the efficient reconversion of drug-tolerant cells back to normalcy, suggesting that such heterogeneity within cancer cell populations might provide evolutionary advantage to increase the pool of drug tolerant cells poising a prospective path towards drug resistance. Citation Format: Fernando Lopez-Diaz, Mei-Chong Wendy Lee, Muhammad Tariq, Shahid Khan, Yelena Dayn, Charlie Vaske, Nader Pourmand, Beverly M. Emerson. Single-cell RNA sequencing reveals phenotypic plasticity of drug tolerant, clonal populations of cancer cells. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Drug Sensitivity and Resistance: Improving Cancer Therapy; Jun 18-21, 2014; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(4 Suppl): Abstract nr A09.

Recombinant Interleukin-1 Receptor Antagonist Conjugated to Superparamagnetic Iron Oxide Nanoparticles for Theranostic Targeting of Experimental Glioblastoma

Cerebral edema commonly accompanies brain tumors and contributes to neurologic symptoms. The role of the interleukin-1 receptor antagonist conjugated to superparamagnetic iron oxide nanoparticles (SPION–IL-1Ra) was assessed to analyze its anti-edemal effect and its possible application as a negative contrast enhancing agent for magnetic resonance imaging (MRI). Rats with intracranial C6 glioma were intravenously administered at various concentrations of IL-1Ra or SPION–IL-1Ra. Brain peritumoral edema following treatment with receptor antagonist was assessed with high-field MRI. IL-1Ra administered at later stages of tumor progression significantly reduced peritumoral edema (as measured by MRI) and prolonged two-fold the life span of comorbid animals in a dose-dependent manner in comparison to control and corticosteroid-treated animals (P < .001). Synthesized SPION–IL-1Ra conjugates had the properties of negative contrast agent with high coefficients of relaxation efficiency. In vitro studies of SPION–IL-1Ra nanoparticles demonstrated high intracellular incorporation and absence of toxic influence on C6 cells and lymphocyte viability and proliferation. Retention of the nanoparticles in the tumor resulted in enhanced hypotensive T2-weighted images of glioma, proving the application of the conjugates as negative magnetic resonance contrast agents. Moreover, nanoparticles reduced the peritumoral edema confirming the therapeutic potency of synthesized conjugates. SPION–IL-1Ra nanoparticles have an anti-edemal effect when administered through a clinically relevant route in animals with glioma. The SPION–IL-1Ra could be a candidate for theranostic approach in neuro-oncology both for diagnosis of brain tumors and management of peritumoral edema.

MicroRNA-204, a direct negative regulator of ezrin gene expression, inhibits glioma cell migration and invasion.

Ezrin is overexpressed in a variety of neoplastic cells and involved in the later stages of tumor progression and metastasis. Ezrin expression can be regulated at both the transcriptional and post-transcriptional levels. We used a combination of bioinformatics and experimental techniques to demonstrate that the miR-204 is a direct negative regulator of ezrin. Overexpression of miR-204 mimics decreased the activity of a luciferase reporter containing the ezrin 3' UTR and led to repression of ezrin protein. In contrast, ectopic expression of miR-204 inhibitor elevated ezrin expression. We also show that miR-204 is down-regulated in a panel of glioma tissues and in high invasive glioma cell lines we examined. Moreover, miR-204 mimics significantly reduced glioma cell migration and invasion, while miR-204 inhibitor generated the opposite results. Finally, overexpression of miR-204 and knockdown of ezrin reduced glioma cell invasion, and these effects could be rescued by re-expression of ezrin. These findings reveal that miR-204 could be partly due to its inhibitory effects on glioma cell migration and invasion through regulating ezrin expression.

Novel patents and cancer therapies for transforming growth factor-beta and urokinase type plasminogen activator: potential use of their interplay in tumorigenesis.

Transforming growth factor beta (TGF-β) plays different roles in health and disease. TGF-β has been assumed as a dual factor in tumor growth, since it can repress epithelial tumor development in early stages, while it acts as a tumor promoter in the late stages of tumor progression. The cancer cells, during cancerogenesis, acquire migration and invasion capacities and finally they metastasize. The urokinase type plasminogen activator (uPA) system, comprised of uPA, the cell surface receptor (uPAR) and plasminogen-plasmin, is involved in the proteolytic degradation of the extracellular matrix and it also regulates several critical cellular events by its capacity to trigger the activation of intracellular signaling pathways. This enables the cancer cell survival, its dissemination, and enhancement of cell malignancy during tumor progression. The expression of both uPA and uPAR is finely regulated in normal development, but their expression is deregulated in cancer. TGF-β regulates uPA expression in cancer cells while uPA, by conversion of plasminogen to active form, plasmin, may release TGF-β from its latent state. Thus, these pathways cross-regulate each other by mutual feedback contributing to tumor progression. Here, we review the specific roles and the interplay between TGF-β and uPA system in cancer cells, the current cancer therapies and the novel patents focused mainly on uPA and TGF-beta ligands and their cell surface receptors respectively. Finally, with regard to the mutual activity of uPA and TGF-β in tumorigenesis, the aim of this review is to expose the potentiality of TGF-β and uPA systems as becoming combinatorial targets for therapies and patents.

NMI and EMT.

NMI and EMT.

The role of neutrophil myeloperoxidase in models of lung tumor development.

Chronic inflammation plays a key tumor-promoting role in lung cancer. Our previous studies in mice demonstrated that neutrophils are critical mediators of tumor promotion in methylcholanthrene (MCA)-initiated, butylated hydroxytoluene (BHT)-promoted lung carcinogenesis. In the present study we investigated the role of neutrophil myeloperoxidase (MPO) activity in this inflammation promoted model. Increased levels of MPO protein and activity were present in the lungs of mice administered BHT. Treatment of mice with N-acetyl lysyltyrosylcysteine amide (KYC), a novel tripeptide inhibitor of MPO, during the inflammatory stage reduced tumor burden. In a separate tumor model, KYC treatment of a Lewis Lung Carcinoma (LLC) tumor graft in mice had no effect on tumor growth, however, mice genetically deficient in MPO had significantly reduced LLC tumor growth. Our observations suggest that MPO catalytic activity is critical during the early stages of tumor development. However, during the later stages of tumor progression, MPO expression independent of catalytic activity appears to be required. Our studies advocate for the use of MPO inhibitors in a lung cancer prevention setting.

Is there any role of mast cell density and microvessel density in cervical squamous cell carcinoma? A histologic study with special reference to CD-34 immunomarker staining.

Background:Mast cells are involved in induction of angiogenesis in the early-stages of tumor development and in modulating blood vessel growth in the later stages of tumor progression.Aims and Objectives:This study was carried out to evaluate the association between mast cell density (MCD) and microvessel density (MVD) in carcinoma in situ (CIS), microinvasive carcinoma (CA) and invasive squamous cell CA of cervix.Materials and Methods:Six cases of CIS, four cases of microinvasive CA and 38 cases of invasive CA were studied over a period of 2 years from August, 2011 to June, 2013. Ten control samples were included in the study. Routine histologic examination was done. Toluidine blue stain was used for MCD determination. Immunohistochemical analysis with CD-34 was done for assessing MVD. Student's t-test was used to calculate the statistical significance of MCD and MVD.Results:Both MCD and MVD increased from normal samples through CIS to invasive cervical CA. In the four cases of microinvasive CA, the MCD and MVD were more than that of the control samples, but less than that of the six cases of CIS.Conclusion:There is a correlation between mast cell accumulation and angiogenesis in CIS, microinvasive CA and invasive cervical squamous cell CA. MCD and MVD in invasive CA exceed those in CIS and microinvasive CA. It gives us an opportunity to postulate that therapeutic strategies against mast cell mediators and angiogenesis may be of benefit in patients of early-stage cervical CA.

HiJAK’d Signaling; the STAT3 Paradox in Senescence and Cancer Progression

Clinical and epidemiological data have associated chronic inflammation with cancer progression. Most tumors show evidence of infiltrating immune and inflammatory cells, and chronic inflammatory disorders are known to increase the overall risk of cancer development. While immune cells are often observed in early hyperplastic lesions in vivo, there remains debate over whether these immune cells and the cytokines they produce in the developing hyperplastic microenvironment act to inhibit or facilitate tumor development. The interleukin-6 (IL-6) family of cytokines, which includes IL-6 and oncostatin M (OSM), among others (LIF, CT-1, CNTF, and CLC), are secreted by immune cells, stromal cells, and epithelial cells, and regulate diverse biological processes. Each of the IL-6 family cytokines signals through a distinct receptor complex, yet each receptor complex uses a shared gp130 subunit, which is critical for signal transduction following cytokine binding. Activation of gp130 results in the activation of Signal Transducer and Activator of Transcription 3 (STAT3), and the Mitogen-Activated Protein Kinase (MAPK) and Phosphatidylinositol 3-Kinase (PI3K) signaling cascades. Tumor suppressive signaling can often be observed in normal cells following prolonged STAT3 activation. However, there is mounting evidence that the IL-6 family cytokines can contribute to later stages of tumor progression in many ways. Here we will review how the microenvironmental IL-6 family cytokine OSM influences each stage of the transformation process. We discuss the intrinsic adaptations a developing cancer cell must make in order to tolerate and circumvent OSM-mediated growth suppression, as well as the OSM effectors that are hijacked during tumor expansion and metastasis. We propose that combining current therapies with new ones that suppress the signals generated from the tumor microenvironment will significantly impact an oncologist’s ability to treat cancer.

Early Tumor Development Captured Through Nondestructive, High Resolution Differential Phase Contrast X-ray Imaging

Although a considerable amount is known about molecular dysregulations in later stages of tumor progression, much less is known about the regulated processes supporting initial tumor growth. Insight into such processes can provide a fuller understanding of carcinogenesis, with implications for cancer treatment and risk assessment. Work from our laboratory suggests that organized substructure emerges during tumor formation. The goal here was to examine the feasibility of using state-of-the-art differential phase contrast X-ray imaging to investigate density differentials that evolve during early tumor development. To this end the beamline for TOmographic Microscopy and Coherent rAdiology experimenTs (TOMCAT) at the Swiss Light Source was used to examine the time-dependent assembly of substructure in developing tumors. Differential phase contrast (DPC) imaging based on grating interferometry as implemented with TOMCAT, offers sensitivity to density differentials within soft tissues and a unique combination of high resolution coupled with a large field of view that permits the accommodation of larger tissue sizes (1 cm in diameter), difficult with other imaging modalities.

Abstract PR04: The Six2 homeoprotein mediates breast cancer metastasis via repressing E-cadherin

Abstract Homeobox genes are master regulators of embryogenesis and it is widely known that misexpression of these transcription factors can lead to tumorigenesis/ metastasis. The Six1 homeoprotein has been implicated in tumor onset and metastasis of many different cancers, including breast cancer. However, little is known about whether related homeoproteins in the Six family can affect tumor onset or progression. Recent studies have shown that while Six1 knockdown dramatically decreases metastasis, knockdown cells that are capable of metastasizing have upregulated a related family member, Six2. Interestingly, Six2 regulates stem/ progenitor cell populations and maintains a mesenchymal progenitor phenotype in the developing kidney; however, the role of Six2 in breast cancer progression has not been explored. Here, we demonstrate for the first time that up-regulation of Six2 in breast cancer cells can promote metastasis in a mechanism that differs from its related family member, Six1. Knockdown (KD) of Six2 in 66cl4 mouse mammary carcinoma cells significantly decreases lung metastasis in an immune-competent orthotopic mouse model, as compared to control KD. In contrast to what is seen with Six1 KD in the same orthotopic mouse model, no significant inhibition of primary tumor size was observed with Six2 knockdown, suggesting that unlike Six1, the functions of Six2 may be confined to later stages of tumor progression. Overexpression of Six2 in the weakly metastatic 4TO7 mouse mammary carcinoma cell line led to changes in cell morphology, increased anchorage independent growth and significantly enhanced lung metastasis in an immune competent mouse model. Microarray analysis was performed to determine the mechanism by which Six2 mediates metastasis and the epithelial marker E-Cadherin, whose loss has been implicated in the metastatic potential of many cancers, was dramatically downregulated in the 4TO7-Six2 expressing cells. Importantly, restoration of E-cadherin expression reduced lung metastasis induced by Six2 and increased survival of the animals. We further determine that repression of E-cadherin by Six2 is mediated via multiple mechanisms. SIP1/Zeb2 (zinc finger E box binding homeobox2), an epithelial to mesenchymal transition (EMT) inducer, is increased in cells overexpressing Six2, and Zeb2 KD in these cells reverts E-cadherin expression back to the level as that observed in the control cells and importantly leads to a reduction in metastasis in vivo. In addition, we find that Six2 may also repress E-cadherin though an epigenetic mechanism, since repression of E-cadherin downstream of Six2 can be reversed by inhibiting DNA methylation. Finally, analysis of Six2 expression from public microarray datasets indicates that Six2 is increased in breast cancers compared to normal breast tissue and that high expression of SIX2 correlates with poor prognosis (distant metastasis free survival, overall survival and relapse free survival) in 1881 human breast tumors examined using the GOBO (Gene Expression-Based Outcome for Breast Cancer Online) database. Moreover, a reverse correlation of E-cadherin and Six2 in breast cancer datasets suggest that Six2 promotes loss of E-cadherin in human breast cancer. Together, these data demonstrate that Six2 is a specific regulator of the metastatic process, through regulating E-cadherin expression. This abstract is also presented as Poster B094. Citation Format: Chu-An Wang, Paul Jedlicka, Aik-Choon Tan, Catherine Pham, Vadym Zaberezhnvv, Heide Ford. The Six2 homeoprotein mediates breast cancer metastasis via repressing E-cadherin. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr PR04.

Tanespimycin and Tipifarnib Exhibit Synergism in Inducing Apoptosis in Melanoma Cell Lines From Later Stages of Tumor Progression

Many anticancer strategies rely on efficient induction of apoptosis. The need for development of drug combinations with a strong pro-apoptotic activity is of particular interest in melanoma resistant to currently available chemotherapeutic regimes. We studied the pro-apoptotic properties of combination of tanespimycin + tipifarnib in five melanoma cell lines representing various stages of tumor progression. Our results show that in cells derived from vertical- and metastatic-phase the combination of tested drugs is strongly cytotoxic and efficient in inducing apoptosis, as evidenced by activation of caspase-9 and caspase-3 and enhanced fragmentation of DNA.

GC protein-derived macrophage-activating factor decreases α-N-acetylgalactosaminidase levels in advanced cancer patients

α-N-acetylgalactosaminidase (nagalase) accumulates in the serum of cancer patients and its activity correlates with tumor burden, aggressiveness and clinical disease progression. The administration of GC protein-derived macrophage-activating factor (GcMAF) to cancer patients with elevated levels of nagalase has been associated with a decrease of serum nagalase activity and with significant clinical benefits. Here, we report the results of the administration of GcMAF to a heterogeneous cohort of patients with histologically diverse, advanced neoplasms, generally considered as “incurable” diseases. In most cases, GcMAF therapy was initiated at late stages of tumor progression. As this is an open-label, non-controlled, retrospective analysis, caution must be employed when establishing cause-effect relationships between the administration GcMAF and disease outcome. However, the response to GcMAF was generally robust and some trends emerged. All patients (n = 20) presented with elevated serum nagalase activity, well above normal values. All patients but one showed a significant decrease of serum nagalase activity upon weekly GcMAF injections. Decreased nagalase activity was associated with improved clinical conditions and no adverse side effects were reported. The observations reported here confirm and extend previous results and pave the way to further studies aimed at assessing the precise role and indications for GcMAF-based anticancer immunotherapy.

The DNA damage checkpoint precedes activation of ARF in response to escalating oncogenic stress during tumorigenesis

Oncogenic stimuli trigger the DNA damage response (DDR) and induction of the alternative reading frame (ARF) tumor suppressor, both of which can activate the p53 pathway and provide intrinsic barriers to tumor progression. However, the respective timeframes and signal thresholds for ARF induction and DDR activation during tumorigenesis remain elusive. Here, these issues were addressed by analyses of mouse models of urinary bladder, colon, pancreatic and skin premalignant and malignant lesions. Consistently, ARF expression occurred at a later stage of tumor progression than activation of the DDR or p16(INK4A), a tumor-suppressor gene overlapping with ARF. Analogous results were obtained in several human clinical settings, including early and progressive lesions of the urinary bladder, head and neck, skin and pancreas. Mechanistic analyses of epithelial and fibroblast cell models exposed to various oncogenes showed that the delayed upregulation of ARF reflected a requirement for a higher, transcriptionally based threshold of oncogenic stress, elicited by at least two oncogenic 'hits', compared with lower activation threshold for DDR. We propose that relative to DDR activation, ARF provides a complementary and delayed barrier to tumor development, responding to more robust stimuli of escalating oncogenic overload.

Expression and Functional Significance of Ezrin in Human Brain Astrocytoma

Ezrin is overexpressed in a variety of neoplastic cells and is involved in the later stages of tumor progression and metastasis. The present study investigated the expression and functional significance of ezrin in human brain astrocytoma. Ezrin expression was examined in specimens from healthy human brains (10 autopsies) or human astrocytoma (107 cases) by immunohistochemistry. All healthy specimens were negative for ezrin expression, while this expression was positive in a great majority of human astrocytoma tissues (96/107; 89.7%; p < 0.05 vs. healthy). Ezrin expression was positively correlated with tumor grade (r = 0.551, p < 0.01). Analysis of clinicopathologic data revealed that the post-operation disease-free survival times were significantly (p < 0.001) different between those with a strong positive ezrin expression and those with a weak or negative expression. Specifically, median DFS in patients with a strongly positive ezrin expression was 13 months (range 2-46 months), while it was significantly (p < 0.001) longer in patients with weakly positive or negative expression (median of 28 months, range 6-56 months). In conclusion, there is a strong association between ezrin expression and increased malignancy in astrocytoma. Thus, enhanced ezrin expression may play an important role in the development of astrocytoma. Our results further indicate that ezrin may be useful for grading of astrocytoma and as a molecular marker for the prognosis.

Elevated Maspin Expression Is Associated with Better Overall Survival in Esophageal Squamous Cell Carcinoma (ESCC)

Tumor suppressor maspin is a differentially regulated gene in the progression of many types of cancer. While the biological function of maspin in blocking tumor invasion and metastasis is consistent with the loss of maspin expression at the late stage of tumor progression, the differential expression and the biological significance of maspin in early stage of tumor progression appear to be complex and remain to be elucidated. In the current study, we examined the expression of maspin in 84 esophageal squamous cell carcinoma (ESCC) cases (stages I–III) and 55 non-tumor adjacent esophageal tissue specimens by immunohistochemical (IHC) staining. The correlation of maspin with clinicopathological parameters was analyzed. Compared to normal esophageal squamous tissue where 80% (47/55) of the cases expressed maspin at a low to moderate level, all ESCC specimens (100% (84/84)) were positive for maspin expression at a moderate to high level. ESCC with low or moderate maspin expression had significantly shorter postoperative survival rates compared to those that had high maspin expression (p<0.001). Since the correlation of maspin with ESCC histology and the correlation of maspin with ESCC prognosis seem to be at odds, we further investigated the biological function of maspin in ESCC using the established ESCC cell lines. The expression of maspin in five human esophageal squamous cancer cell lines (T12, E450, KYSE150, EC109, and KYSE510) was examined by the Western blot. ESCC cell line KYSE510 that did not express maspin and was stably transfected by maspin cDNA or an empty vector. The resulting transfected cells were characterized in vitro. Maspin expression significantly inhibited cell proliferation, motility and matrigel invasion. Taken together, our data suggest that the transient up-regulation of maspin in the early development of ESCC may be a defense mechanism against further transition towards more malignant phenotypes, ultimately slowing down ESCC tumor progression.

Integrin signaling in control of tumor growth and progression

Interactions with the extracellular matrix (ECM) provide cells with physical and chemical cues that act in concert with growth factors to support survival and proliferation. Transmembrane receptors of the integrin family mediate ECM attachment and play important roles in sensing and responding to ECM properties. Integrin signaling involves large integrin-associated intracellular protein complexes that act as anchors for the cytoskeleton and as signaling hotspots where enzymes and substrates are concentrated. Moreover, many different growth factor signaling cascades are amplified when cells are attached to the ECM. Integrins are involved in many pathologies; here we focus on their roles in cancer. Although “anchorage-independence” is a hallmark of cancer cells, genetic studies clearly show that integrins and associated proteins provide essential support for early tumor development and growth. Integrins also provide support during later stages of tumor progression but in some scenarios they appear to have suppressive activity, which is currently not understood.

Inflammation and Gliomagenesis: Bi-Directional Communication at Early and Late Stages of Tumor Progression

Inflammation has been closely linked to various forms of cancer. Less is known about the role of inflammation in glioma, especially at the initiation stage. In this review, we first describe the unique features of the immune system in the brain. We then discuss the current understanding of the mechanisms by which glioma cells modulate the immune system, especially how bi-directional communications between immune cells and glioma cells create an immunosuppressed microenvironment that promotes tumor survival and growth. We also address the potential tumor-initiating roles of inflammation in glioma. Finally, we describe several immunotherapy approaches currently being developed to reverse these interactions and stimulate the immune system to eliminate glioma cells.