GIPC1 regulates MACC1-driven metastasis.

Background: Identification of cancer metastasis-relevant molecular networks is desired to provide the basis for understanding and developing intervention strategies. Here we address the role of GIPC1 in the process of MACC1-driven metastasis. MACC1 is a prognostic indicator for patient metastasis formation and metastasis-free survival. MACC1 controls gene transcription, promotes motility, invasion and proliferation of colon cancer cells in vitro, and causes tumor growth and metastasis in mice. Methods: By using yeast-two-hybrid assay, mass spectrometry, co-immunoprecipitation and peptide array we analyzed GIPC1 protein binding partners, by using the MACC1 gene promoter and chromatin immunoprecipitation and electrophoretic mobility shift assay we probed for GIPC1 as transcription factor. We employed GIPC1/MACC1-manipulated cell lines for in vitro and in vivo analyses, and we probed the GIPC1/MACC1 impact using human primary colorectal cancer (CRC) tissue. Results: We identified MACC1 and its paralogue SH3BP4 as protein binding partners of the protein GIPC1, and we also demonstrated the binding of GIPC1 as transcription factor to the MACC1 promoter (TSS to -60 bp). GIPC1 knockdown reduced endogenous, but not CMV promoter-driven MACC1 expression, and diminished MACC1-induced cell migration and invasion. GIPC1 suppression reduced tumor growth and metastasis in mice intrasplenically transplanted with MACC1-overexpressing CRC cells. In human primary CRC specimens, GIPC1 correlates with MACC1 expression and is of prognostic value for metastasis formation and metastasis-free survival. Combination of MACC1 and GIPC1 expression improved patient survival prognosis, whereas SH3BP4 expression did not show any prognostic value. Conclusions: We identified an important, dual function of GIPC1 - as protein interaction partner and as transcription factor of MACC1 - for tumor progression and cancer metastasis.

Real-world evidence research based on big data: Motivation-challenges-success factors.

BACKGROUND: In recent years there has been an increasing, partially also critical interest in understanding the potential benefits of generating real-world evidence (RWE) in medicine. OBJECTIVES: The benefits and limitations of RWE in the context of randomized controlled trials (RCTs) are described along with a view on how they may complement each other as partners in the generation of evidence for clinical oncology. Moreover, challenges and success factors in building an effective RWE network of cooperating cancer centers are analyzed and discussed. MATERIAL AND METHODS: This article is based on a selective literature search (predominantly 2015-2017) combined with our practical experience to date in establishing European oncology RWE networks. RESULTS: RWE studies can be highly valuable and complementary to RCTs due to their high external validity. If cancer centers successfully address the various challenges in the establishment of an effective RWE study network and in the consequent execution of studies, they may efficiently generate high-quality research findings on treatment effectiveness and safety. Concerns pertaining to data privacy are of utmost importance and discussed accordingly. Securing data completeness, accuracy, and a common data structure on routinely collected disease and treatment-related data of patients with cancer is a challenging task that requires high engagement of all participants in the process. CONCLUSION: Based on the discussed prerequisites, the analysis of comprehensive and complex real-world data in the context of a RWE study network represents an important and promising complementary partner to RCTs. This enables research into the general quality of cancer care and can permit comparative effectiveness studies across partner centers. Moreover, it will provide insights into a broader optimization of cancer care, refined therapeutic strategies for patient subgroups as well as avenues for further research in oncology.

Loss-of-function uORF mutations in human malignancies.

Ribosome profiling revealed widespread translational activity at upstream open reading frames (uORFs) and validated uORF-mediated translational control as a commonly repressive mechanism of gene expression. Translational activation of proto-oncogenes through loss-of-uORF mutations has been demonstrated, yet a systematic search for cancer-associated genetic alterations in uORFs is lacking. Here, we applied a PCR-based, multiplex identifier-tagged deep sequencing approach to screen 404 uORF translation initiation sites of 83 human tyrosine kinases and 49 other proto-oncogenes in 308 human malignancies. We identified loss-of-function uORF mutations in EPHB1 in two samples derived from breast and colon cancer, and in MAP2K6 in a sample of colon adenocarcinoma. Both mutations were associated with enhanced translation, suggesting that loss-of-uORF-mediated translational induction of the downstream main protein coding sequence may have contributed to carcinogenesis. Computational analysis of whole exome sequencing datasets of 464 colon adenocarcinomas subsequently revealed another 53 non-recurrent somatic mutations functionally deleting 22 uORF initiation and 31 uORF termination codons, respectively. These data provide evidence for somatic mutations affecting uORF initiation and termination codons in human cancer. The insufficient coverage of uORF regions in current whole exome sequencing datasets demands for future genome-wide analyses to ultimately define the contribution of uORF-mediated translational deregulation in oncogenesis.

C/EBPß regulates homeostatic and oncogenic gastric cell proliferation.

Cancer of the stomach is among the leading causes of death from cancer worldwide. The transcription factor C/EBPß is frequently overexpressed in gastric cancer and associated with the suppression of the differentiation marker TFF1. We show that the murine C/EBPß knockout stomach displays unbalanced homeostasis and reduced cell proliferation and that tumorigenesis of human gastric cancer xenograft is inhibited by knockdown of C/EBPß. Cross-species comparison of gene expression profiles between C/EBPß-deficient murine stomach and human gastric cancer revealed a subset of tumors with a C/EBPß signature. Within this signature, the RUNX1t1 tumor suppressor transcript was down-regulated in 38 % of gastric tumor samples. The RUNX1t1 promoter was frequently hypermethylated and ectopic expression of RUNX1t1 in gastric cancer cells inhibited proliferation and enhanced TFF1 expression. These data suggest that the tumor suppressor activity of both RUNX1t1 and TFF1 are mechanistically connected to C/EBPß and that cross-regulation between C/EBPß-RUNX1t1-TFF1 plays an important role in gastric carcinogenesis. KEY MESSAGE: C/EBPß controls proliferation and differentiation balance in the stomach. Homeostatic differentiation/proliferation balance is altered in gastric cancer. RUNX1t1 is a C/EBPß-associated tumor suppressor. RUNX1t1 negatively regulates C/EBPß pro-oncogenic functions.

High MACC1 expression in combination with mutated KRAS G13 indicates poor survival of colorectal cancer patients.

BACKGROUND: The metastasis-associated in colon cancer 1 (MACC1) gene has been identified as prognostic biomarker for colorectal cancer (CRC). Here, we aimed at the refinement of risk assessment by separate and combined survival analyses of MACC1 expression with any of the markers KRAS mutated in codon 12 (KRAS G12) or codon 13 (KRAS G13), BRAF V600 mutation and MSI status in a retrospective study of 99 CRC patients with tumors UICC staged I, II and III. FINDINGS: We showed that only high MACC1 expression (HR: 6.09, 95% CI: 2.50-14.85, P < 0.001) and KRAS G13 mutation (HR: 5.19, 95% CI: 1.06-25.45, P = 0.042) were independent prognostic markers for shorter metastasis-free survival (MFS). Accordingly, Cox regression analysis revealed that patients with high MACC1 expression and KRAS G13 mutation exhibited the worst prognosis (HR: 14.48, 95% CI: 3.37-62.18, P < 0.001). Patients were classified based on their molecular characteristics into four clusters with significant differences in MFS (P = 0.003) by using the SPSS 2-step cluster function and Kaplan-Meier survival analysis. CONCLUSION: According to our results, patients with high MACC1 expression and mutated KRAS G13 exhibited the highest risk for metachronous metastases formation. Moreover, we demonstrated that the "Traditional pathway" with an intermediate risk for metastasis formation can be further subdivided by assessing MACC1 expression into a low and high risk group with regard to MFS prognosis. This is the first report showing that identification of CRC patients at high risk for metastasis is possible by assessing MACC1 expression in combination with KRAS G13 mutation.

The course of gastric cancer following surgery is associated with genetic variations of the interleukin-1 receptor antagonist and interleukin-1ß.

BACKGROUND: Inflammation, especially the cytokine response of the IL-1 family, has been shown to influence susceptibility to gastric cancer. In addition, several other pro-inflammatory cytokines have been demonstrated to influence metastasis and resistance to chemotherapy. Therefore, genetic variations within these genes may not only affect susceptibility but also influence the outcome of gastric cancer patients. A limited number of studies showed indeed an association of IL-1ß and IL-1RN variations with survival of gastric cancer patients. However, results are inconsistent, possibly because of different patient cohorts and different therapies. METHODS: In this retrospective cohort study we genotyped 154 patients with gastric cancer for IL-1ß and IL-1RN variations. Patients had undergone pathologically proven R0 resection and had received no additional adjuvant treatment. RESULTS: We show here a protective association with disease-free survival for both heterozygous genotypes, IL-1ß SNP C-511T (rs16944) and IL-1RN VNTR. The combination of both heterozygous genotypes is the strongest predictor independent of UICC stage. CONCLUSION: Genetic variations in the IL-1ß and IL-1RN genes influence disease progression in gastric cancer. Screening for these genetic variations might help to stratify therapies for gastric cancer patients in the future.

RAGE mediates S100A4-induced cell motility via MAPK/ERK and hypoxia signaling and is a prognostic biomarker for human colorectal cancer metastasis.

Survival of colorectal cancer patients is strongly dependent on development of distant metastases. S100A4 is a prognostic biomarker and inducer for colorectal cancer metastasis. Besides exerting intracellular functions, S100A4 is secreted extracellularly. The receptor for advanced glycation end products (RAGE) is one of its interaction partners. The impact of the S100A4-RAGE interaction for cell motility and metastasis formation in colorectal cancer has not been elucidated so far. Here we demonstrate the RAGE-dependent increase in migratory and invasive capabilities of colorectal cancer cells via binding to extracellular S100A4. We show the direct interaction of S100A4 and RAGE, leading to hyperactivated MAPK/ERK and hypoxia signaling. The S100A4-RAGE axis increased cell migration (P<0.005) and invasion (P<0.005), which was counteracted with recombinant soluble RAGE and RAGE-specific antibodies. In colorectal cancer patients, not distantly metastasized at surgery, high RAGE expression in primary tumors correlated with metachronous metastasis, reduced overall (P=0.022) and metastasis-free survival (P=0.021). In summary, interaction of S100A4-RAGE mediates S100A4-induced colorectal cancer cell motility. RAGE by itself represents a biomarker for prognosis of colorectal cancer. Thus, therapeutic approaches targeting RAGE or intervening in S100A4-RAGE-dependent signaling early in tumor progression might represent alternative strategies restricting S100A4-induced colorectal cancer metastasis.

Preclinical study on combined chemo- and nonviral gene therapy for sensitization of melanoma using a human TNF-alpha expressing MIDGE DNA vector.

Nonviral gene therapy represents a realistic option for clinical application in cancer treatment. This preclinical study demonstrates the advantage of using the small-size MIDGE(®) DNA vector for improved transgene expression and therapeutic application. This is caused by significant increase in transcription efficiency, but not by increased intracellular vector copy numbers or gene transfer efficiency. We used the MIDGE-hTNF-alpha vector for high-level expression of hTNF-alpha in vitro and in vivo for a combined gene therapy and vindesine treatment in human melanoma models. The MIDGE vector mediated high-level hTNF-alpha expression leads to sensitization of melanoma cells towards vindesine. The increased efficacy of this combination is mediated by remarkable acceleration and increase of initiator caspase 8 and 9 and effector caspase 3 and 7 activation. In the therapeutic approach, the nonviral intratumoral in vivo jet-injection gene transfer of MIDGE-hTNF-alpha in combination with vindesine causes melanoma growth inhibition in association with increased apoptosis in A375 cell line or patient derived human melanoma xenotransplant (PDX) models. This study represents a proof-of-concept for an anticipated phase I clinical gene therapy trial, in which the MIDGE-hTNF-alpha vector will be used for efficient combined chemo- and nonviral gene therapy of malignant melanoma.

Perioperative FOLFOX4 chemotherapy and surgery versus surgery alone for resectable liver metastases from colorectal cancer (EORTC 40983): long-term results of a randomised, controlled, phase 3 trial.

BACKGROUND: Previous results of the EORTC intergroup trial 40983 showed that perioperative chemotherapy with FOLFOX4 (folinic acid, fluorouracil, and oxaliplatin) increases progression-free survival (PFS) compared with surgery alone for patients with initially resectable liver metastases from colorectal cancer. Here we present overall survival data after long-term follow-up. METHODS: This randomised, controlled, parallel-group, phase 3 study recruited patients from 78 hospitals across Europe, Australia, and Hong Kong. Eligible patients aged 18-80 years who had histologically proven colorectal cancer and up to four liver metastases were randomly assigned (1:1) to either perioperative FOLFOX4 or surgery alone. Perioperative FOLFOX4 consisted of six 14-day cycles of oxaliplatin 85mg/m(2), folinic acid 200 mg/m(2) (DL form) or 100 mg/m(2) (L form) on days 1-2 plus bolus, and fluorouracil 400 mg/m(2) (bolus) and 600 mg/m(2) (continuous 22 h infusion), before and after surgery. Patients were centrally randomised by minimisation, adjusting for centre and risk score and previous adjuvant chemotherapy to primary surgery for colorectal cancer, and the trial was open label. Analysis of overall survival was by intention to treat in all randomly assigned patients. FINDINGS: Between Oct 10, 2000, and July 5, 2004, 364 patients were randomly assigned to a treatment group (182 patients in each group, of which 171 per group were eligible and 152 per group underwent resection). At a median follow-up of 8·5 years (IQR 7·6-9·5), 107 (59%) patients in the perioperative chemotherapy group had died versus 114 (63%) in the surgery-only group (HR 0·88, 95% CI 0·68-1·14; p=0·34). In all randomly assigned patients, median overall survival was 61·3 months (95% CI 51·0-83·4) in the perioperative chemotherapy group and 54·3 months (41·9-79·4) in the surgery alone group. 5-year overall survival was 51·2% (95% CI 43·6-58·3) in the perioperative chemotherapy group versus 47·8% (40·3-55·0) in the surgery-only group. Two patients in the perioperative chemotherapy group and three in the surgery-only group died from complications of protocol surgery, and one patient in the perioperative chemotherapy group died possibly as a result of toxicity of protocol treatment. INTERPRETATION: We found no difference in overall survival with the addition of perioperative chemotherapy with FOLFOX4 compared with surgery alone for patients with resectable liver metastases from colorectal cancer. However, the previously observed benefit in PFS means that perioperative chemotherapy with FOLFOX4 should remain the reference treatment for this population of patients. FUNDING: Norwegian and Swedish Cancer Societies, Cancer Research UK, Ligue Nationale Contre Cancer, US National Cancer Institute, Sanofi-Aventis.

Current status of gene therapy for cancer.

PURPOSE OF REVIEW: In recent years, remarkable progress has been made in the development of cancer gene therapy into an applicable treatment modality for immunogene, suicide, gene correction and oncolytic therapies. New exciting developments for gene suppression or miRNA therapies are under way. The efforts are focused on more efficient and specific attack at known and novel targets, improvement of vector delivery and therapeutic efficacy. In this review, promising and new gene therapy approaches and clinical studies are briefly discussed to highlight important future directions of preclinical and clinical efforts. RECENT FINDINGS: Apart from progress for vector development and even more important, improvements for suicide, T-cell-based, oncolytic virus therapies were achieved. In addition, new emerging therapies are successfully developed, which are particularly promising for siRNA-based technologies applied to gene suppression therapy. Novel approaches, such as transcription factor ODN-based decoy, complement the spectrum of current cancer gene therapy. SUMMARY: In summary, cancer gene therapy has made remarkable progress in the improvement/refinement of existing strategies and delivery systems. The field is moving toward a therapeutic option, which will also be applicable for the treatment of disseminated metastases. Furthermore, numerous new approaches are about to be translated in clinical trials.

Promoter identification and transcriptional regulation of the metastasis gene MACC1 in colorectal cancer.

MACC1, Metastasis associated in colon cancer 1, is a newly identified prognostic biomarker for colorectal cancer metastasis and patient survival, when determined in the primary tumor or patient blood. MACC1 induces cell motility and proliferation in cell culture and metastasis in mouse models. MACC1 acts as a transcriptional regulator of the receptor tyrosine kinase gene Met via binding to its promoter. However, no information about the promoter of the MACC1 gene and its transcriptional regulation has been reported so far. Here we report the identification of the MACC1 promoter using a promoter luciferase construct that directs transcription of MACC1. To gain insights into the essential domains within this promoter region, we constructed 5' truncated deletion constructs. Our results show that the region from -426 to -18 constitutes the core promoter and harbors functional motifs for the binding of AP-1, Sp1, and C/EBP transcription factors as validated by site directed mutagenesis study. Using electrophoretic mobility shift assay and chromatin immunoprecipitation assay, we demonstrated the physical interaction of these transcription factors to a minimal essential MACC1 core promoter sequence. Knock down of these transcription factors using RNAi strategy reduced MACC1 expression (P < 0.001), and resulted in decrease of cell migration (P < 0.01) which could be specifically rescued by ectopic overexpression of MACC1. In human colorectal tumors, expression levels of c-Jun and Sp1 correlated significantly to MACC1 (P = 0.0007 and P = 0.02, respectively). Importantly, levels of c-Jun and Sp1 also showed significant correlation to development of metachronous metastases (P = 0.01 and P = 0.001, respectively). This is the first study identifying the MACC1 promoter and its transcriptional regulation by AP-1 and Sp1. Knowledge of the transcriptional regulation of the MACC1 gene will implicate in enhanced understanding of its role in cancer progression and metastasis.

Performance of high quality minicircle DNA for in vitro and in vivo gene transfer.

Plasmid DNA is frequently used particularly for nonviral gene therapy. Conventional plasmid DNA contains bacterial backbone and resistance gene sequences, as well as immunogenic CpG motifs. These components are not required for transgene expression. They represent a potential risk for safe clinical application and reduce gene transfer rates as well as transgene expression. To overcome these drawbacks, the minicircle technology is removing such sequences, to improve performance and also to reduce DNA size. Here, we show the effective production of luciferase, GFP, or lacZ-carrying minicircle DNA with high yield and reproducible high quality. They are used for lipofection or electroporation gene transfer into human melanoma and colon carcinoma cell lines. Comparison of respective parental plasmid and minicircle-mediated luciferase gene transfer shows improved luciferase expression by minicircle in all cell lines. This is not associated with increase in intracellular minicircle copy numbers after lipofection or electroporation. The minicircles rather mediate enhanced transgene mRNA transcription compared to their parental plasmids. In addition, FACS analysis revealed increase in counts of GFP positive cells after minicircle gene transfer, indicating higher gene transfer rates. Furthermore, minicircle showed also improved performance in vivo after jet-injection gene transfer. Therefore, availability of minicircles with reproducible high quality and sufficient amount makes them an applicable and effective alternative to conventional plasmid gene vectors.

HER2/neu DNA vaccination by intradermal gene delivery in a mouse tumor model: Gene gun is superior to jet injector in inducing CTL responses and protective immunity.

DNA vaccines are potential tools for the induction of immune responses against both infectious disease and cancer. The dermal application of DNA vaccines is of particular interest since the epidermal and dermal layers of the skin are characterized by an abundance of antigen-presenting cells (APCs). The aim of our study was to compare tumor protection as obtained by two different methods of intradermal DNA delivery (gene gun and jet injector) in a well-established HER2/neu mouse tumor model. BALB/c mice were immunized twice with a HER2/neu-coding plasmid by gene gun or jet injector. Mice were then subcutaneously challenged with HER2/neu(+) syngeneic D2F2/E2 tumor cells. Protection against subsequent challenges with tumor cells as well as humoral and T-cell immune responses induced by the vaccine were monitored. Gene gun immunization was far superior to jet injector both in terms of tumor protection and induction of HER2/neu-specific immune responses. After gene gun immunization, 60% of the mice remained tumor-free until day 140 as compared with 25% after jet injector immunization. Furthermore, gene gun vaccination was able to induce both a strong T(H)1-polarized T-cell response with detectable cytotoxic T-lymphocyte (CTL) activity and a humoral immune response against HER2/neu, whereas the jet injector was not. Although the disadvantages that were associated with the use of the jet injector in our model may be overcome with methodological modifications and/or in larger animals, which exhibit a thicker skin and/or subcutaneous muscle tissue, we conclude that gene gun delivery constitutes the method of choice for intradermal DNA delivery in preclinical mouse models and possibly also for the clinical development of DNA-based vaccines.

Circulating MACC1 transcripts in colorectal cancer patient plasma predict metastasis and prognosis.

BACKGROUND: Metastasis is the most frequent cause of treatment failure and death in colorectal cancer. Early detection of tumors and metastases is crucial for improving treatment strategies and patient outcome. Development of reliable biomarkers and simple tests routinely applicable in the clinic for detection, prognostication, and therapy monitoring is of special interest. We recently identified the novel gene Metastasis-Associated in Colon Cancer 1 (MACC1), a key regulator of the HGF/Met-pathway. MACC1 is a strong prognostic biomarker for colon cancer metastasis and allows identification of high-risk subjects in early stages, when determined in patients' primary tumors. To overcome the limitation of a restricted number of molecular analyses in tumor tissue, the establishment of a non-invasive blood test for early identification of high-risk cancer patients, for monitoring disease course and therapy response is strongly needed. METHODOLOGY/PRINCIPAL FINDINGS: For the first time, we describe a non-invasive assay for quantification of circulating MACC1 transcripts in blood of more than 300 colorectal cancer patients. MACC1 transcript levels are increased in all disease stages of the cancer patients compared to tumor-free volunteers. Highest MACC1 levels were determined in individuals with metastases (all P<0.05). Importantly, high MACC1 levels correlate with unfavorable survival (P<.0001). Combining MACC1 with circulating transcripts of the metastasis gene S100A4, a transcriptional target of the Wnt/ß-catenin-pathway, improves survival prediction for newly diagnosed cancer patients. CONCLUSION/SIGNIFICANCE: This blood-based assay for circulating MACC1 transcripts, which can be quantitated on a routine basis, is clinically applicable for diagnosis, prognosis, and therapeutic monitoring of cancer patients. Here we demonstrate the diagnostic and prognostic value of circulating MACC1 transcripts in patient plasma for metastasis and survival. Since MACC1 represents a promising target for anti-metastatic therapies, circulating MACC1 transcripts may prove to be an ideal read-out for monitoring therapeutic response of future interventions targeting MACC1-induced metastasis in cancer patients.

Integrative marker analysis allows risk assessment for metastasis in stage II colon cancer.

OBJECTIVES: Individualized risk assessment in patients with UICC stage II colon cancer based on a panel of molecular genetic alterations. BACKGROUND: Risk assessment in patients with colon cancer and localized disease (UICC stage II) is not sufficiently reliable. Development of metachronous metastasis is assumed to be governed largely by individual tumor genetics. METHODS: Fresh frozen tissue from 232 patients (T3-4, N0, M0) with complete tumor resection and a median follow-up of 97 months was analyzed for microsatellite stability, KRAS exon 2, and BRAF exon 15 mutations. Gene expression of the WNT-pathway surrogate marker osteopontin and the metastasis-associated genes SASH1 and MACC1 was determined for 179 patients. The results were correlated with metachronous distant metastasis risk (n = 22 patients). RESULTS: Mutations of KRAS were detected in 30% patients, mutations of BRAF in 15% patients, and microsatellite instability in 26% patients. Risk of recurrence was associated with KRAS mutation (P = 0.033), microsatellite stable tumors (P = 0.015), decreased expression of SASH1 (P = 0.049), and increased expression of MACC1 (P < 0.001). MACC1 was the only independent parameter for recurrence prediction (hazard ratio: 6.2; 95% confidence interval: 2.4-16; P < 0.001). Integrative 2-step cluster analysis allocated patients into 4 groups, according to their tumor genetics. KRAS mutation, BRAF wild type, microsatellite stability, and high MACC1 expression defined the group with the highest risk of recurrence (16%, 7 of 43), whereas BRAF wild type, microsatellite instability, and low MACC1 expression defined the group with the lowest risk (4%, 1 of 26). CONCLUSIONS: MACC1 expression predicts development of metastases, outperforming microsatellite stability status, as well as KRAS/BRAF mutation status.

Systemic shRNA mediated knock down of S100A4 in colorectal cancer xenografted mice reduces metastasis formation.

The metastasis-inducing protein S100A4 was found to be a prognostic indicator for the development of metachronous metastases. S100A4 expression levels correlate with the formation of human colorectal cancer metastases and shorter patients' survival. Inhibition of S100A4 expression in patients might therefore result in decreased metastasis formation and prolonged survival. In the present study, we used shRNA expression plasmids to inhibit S100A4 expression in the colorectal cancer cell lines HCT116, SW620 and DLD-1. Cell lines with reduced S100A4 expression showed reduced cell migration and invasion in vitro. The knock-down of S100A4 expression also led to significantly diminished formation of liver metastases when intrasplenically transplanted in mice (P = 0.004). We then focused on the therapeutic potential of systemically applied shRNA expression plasmids acting on S100A4 via repeated hydrodynamics-based tail vein injection of plasmid DNA. Mice, intrasplenically transplanted with HCT116 cells and treated systemically with S100A4­shRNA plasmids, showed a decrease of S100A4 and MMP9 expression levels, resulting in significantly reduced liver metastases (P = 0.005). In summary, we show for the first time the intratumoral knock down of S100A4 via systemic application of S100A4­shRNA plasmid DNA, which restricts metastasis formation in a xenografted mouse model of colorectal cancer.

Intratumoral dispersion, retention, systemic biodistribution, and clearance of a small-size tumor necrosis factor-α-expressing MIDGE vector after nonviral in vivo jet-injection gene transfer.

For nonviral applications of therapeutic DNA, highly efficient and safe vector systems are of crucial importance. In the majority of nonviral approaches plasmid vectors are in use. A novel minimalistic gene expression vector (MIDGE) has been developed to overcome the limitations of plasmid vectors. This small-size double-stranded linear DNA vector has shown improved transgene expression. However, only limited knowledge on uptake, biodistribution, and clearance of this vector exists. In this study we investigated the intratumoral and systemic biodistribution, clearance, and expression kinetics of the tumor necrosis factor (TNF)-α-carrying MIDGE-CMVhTNF vector in NMRI-nu/nu mice with subcutaneously xenotransplanted human A375 melanoma. Biodistribution was analyzed by quantitative real-time PCR in tumors, blood, and organs 0 to 60 min and 3 to 48 hr after intratumoral jet-injection of 50 µg of MIDGE-CMVhTNF. We examined TNF mRNA expression in tumor tissue and organs, using real-time RT-PCR and TNF-specific ELISA. High levels of MIDGE DNA in the tumor tissue demonstrated efficient gene transfer of the small-size vector, resulting in inhomogeneous DNA dispersion and efficient transgene expression. Intratumoral jet-injection of the vector DNA was accompanied by leakage into the blood circuit and appearance in peripheral organs within 5 min to 6 hr. However, this did not lead to TNF-α expression and was followed by rapid vector clearance resulting in the disappearance of MIDGE DNA 24 hr after gene transfer. These data provide important new information for the kinetics of intratumoral and systemic biodistribution and rapid clearance of the jet-injected small-size MIDGE vector.

SNPs in the coding region of the metastasis-inducing gene MACC1 and clinical outcome in colorectal cancer.

BACKGROUND: Colorectal cancer is one of the main cancers in the Western world. About 90% of the deaths arise from formation of distant metastasis. The expression of the newly identified gene metastasis associated in colon cancer 1 (MACC1) is a prognostic indicator for colon cancer metastasis. Here, we analyzed for the first time the impact of single nucleotide polymorphisms (SNPs) in the coding region of MACC1 for clinical outcome of colorectal cancer patients. Additionally, we screened met proto-oncogene (Met), the transcriptional target gene of MACC1, for mutations. METHODS: We sequenced the coding exons of MACC1 in 154 colorectal tumors (stages I, II and III) and the crucial exons of Met in 60 colorectal tumors (stages I, II and III). We analyzed the association of MACC1 polymorphisms with clinical data, including metachronous metastasis, UICC stages, tumor invasion, lymph node metastasis and patients' survival (n = 154, stages I, II and III). Furthermore, we performed biological assays in order to evaluate the functional impact of MACC1 SNPs on the motility of colorectal cancer cells. RESULTS: We genotyped three MACC1 SNPs in the coding region. Thirteen % of the tumors had the genotype cg (rs4721888, L31V), 48% a ct genotype (rs975263, S515L) and 84% a gc or cc genotype (rs3735615, R804T). We found no association of these SNPs with clinicopathological parameters or with patients' survival, when analyzing the entire patients' cohort. An increased risk for a shorter metastasis-free survival of patients with a ct genotype (rs975263) was observed in younger colon cancer patients with stage I or II (P = 0.041, n = 18). In cell culture, MACC1 SNPs did not affect MACC1-induced cell motility and proliferation. CONCLUSION: In summary, the identification of coding MACC1 SNPs in primary colorectal tumors does not improve the prediction for metastasis formation or for patients' survival compared to MACC1 expression analysis alone. The ct genotype (rs975263) might be associated with a reduced survival for younger colon cancer patients in early stages. However, further studies with larger sample sizes are needed.