Decoy oligodeoxynucleotides as novel cardiovascular drugs for cardiovascular disease

Concomitant targeting of multiple key transcription factors effectively disrupts cancer stem cells enriched in side population of human pancreatic cancer cells

Background

A major challenge in the treatment of pancreatic ductal adenocarcinoma is the failure of chemotherapy, which is likely due to the presence of the cancer stem cells (CSCs).

Objective

To identify side population (SP) cells and characterize s-like properties in human pancreatic cancer cell lines (h-PCCLs) and to exploit the efficacy of concomitant targeting of multiple key transcription factors governing the stemness of pancreatic CSCs in suppressing CSC-like phenotypes.

Methods

Flow cytometry and Hoechst 33342 DNA-binding dye efflux assay were used to sort SP and non-SP (NSP) cells from three h-PCCLs: PANC-1, SW1990, and BxPc-3. The self-renewal ability, invasiveness, migration and drug resistance of SP cells were evaluated. Expression of CSC marker genes was analyzed. Tumorigenicity was assessed using a xenograft model in nude mice. Effects of a complex decoy oligonucleotide (cdODN-SCO) designed to simultaneously targeting Sox2, Oct4 and c-Myc were assessed.

Results

CSCs were enriched in the side proportion (SP) cells contained in the h-PCCLs and they possessed aggressive growth, invasion, migration and drug-resistance properties, compared with NSP cells. SP cells overexpressed stem cell markers CD133 and ALDH1, pluripotency maintaining factors Nanog, Sox2 and Oct4, oncogenic transcription factor c-Myc, signaling molecule Notch1, and drug resistant gene ABCG2. Moreover, SP cells consistently demonstrated significantly greater tumorigenicity than NSP cells in xenograft model of nude mice. CdODN–SOC efficiently suppressed all CSC properties and phenotypes, and minimized the tumorigenic capability of the SP cells and the resistance to chemotherapy. By comparison, the negative control failed to do so.

Conclusion

The findings indicate that targeting the key genes conferring the stemness of CSCs can efficiently eliminate CSC-like phenotypes, and thus may be considered a new approach for cancer therapy. Specifically, the present study establishes the combination of Sox2/Oct4/c-Myc targeting as a potential anti-pancreatic cancer agent worthy of further studies in preclinical settings.

Transcriptional and post-transcriptional mechanisms for oncogenic overexpression of ether à go-go K+ channel

The human ether-à-go-go-1 (h-eag1) K⁺ channel is expressed in a variety of cell lines derived from human malignant tumors and in clinical samples of several different cancers, but is otherwise absent in normal tissues. It was found to be necessary for cell cycle progression and tumorigenesis. Specific inhibition of h-eag1 expression leads to inhibition of tumor cell proliferation. We report here that h-eag1 expression is controlled by the p53−miR-34−E2F1 pathway through a negative feed-forward mechanism. We first established E2F1 as a transactivator of h-eag1 gene through characterizing its promoter region. We then revealed that miR-34, a known transcriptional target of p53, is an important negative regulator of h-eag1 through dual mechanisms by directly repressing h-eag1 at the post-transcriptional level and indirectly silencing h-eag1 at the transcriptional level via repressing E2F1. There is a strong inverse relationship between the expression levels of miR-34 and h-eag1 protein. H-eag1antisense antagonized the growth-stimulating effects and the upregulation of h-eag1 expression in SHSY5Y cells, induced by knockdown of miR-34, E2F1 overexpression, or inhibition of p53 activity. Therefore, p53 negatively regulates h-eag1 expression by a negative feed-forward mechanism through the p53−miR-34−E2F1 pathway. Inactivation of p53 activity, as is the case in many cancers, can thus cause oncogenic overexpression of h-eag1 by relieving the negative feed-forward regulation. These findings not only help us understand the molecular mechanisms for oncogenic overexpression of h-eag1 in tumorigenesis but also uncover the cell-cycle regulation through the p53−miR-34−E2F1−h-eag1 pathway. Moreover, these findings place h-eag1 in the p53−miR-34−E2F1−h-eag1 pathway with h-eag as a terminal effecter component and with miR-34 (and E2F1) as a linker between p53 and h-eag1. Our study therefore fills the gap between p53 pathway and its cellular function mediated by h-eag1.

COL1A1 oligodeoxynucleotides decoy: biochemical and morphologic effects in an acute wound repair model

Type I collagen is an integral component of granulation tissue and scar, that is highly dependent on TGFβ1, a member of a pro-fibrotic family of cytokines, for its promotion and deposition. Blocking COL1A1 gene transcription obstructs type I collagen synthesis, hindering the progress of granulation tissue deposition and fibrosis. Local injections of a double stranded oligodeoxynucleotide (dsODN) decoy, containing the TGFβ1 regulatory element that is located in the distal promoter of the COL1A1 gene, were investigated in a rat polyvinyl alcohol (PVA) sponge granulation tissue implant model. The effects on the granulation tissue deposition by dsODN decoy therapy were evaluated by the synthesis of types I and III collagens as well as ED-A (cellular) fibronectin. Fluorescently labeled dsODN was used to identify the distribution of the decoy molecules in the sponge implant relative to the observed histological effects. Morphological alterations in cells and changes in the organization of connective tissue were documented and evaluated. Collagen levels were reduced by half in implants treated with 10 nM dsODN decoy compared to scrambled dsODN-treated implants. Histologically, dsODN decoy treated implants had an increased cellular density without a corresponding increase in deposited connective tissue. Polarized light birefringence pattern of Sirius red-stained sections showed less collagen fibers accumulating between fibroblasts. The highest concentration of fluorescently labeled dsODN was identified within the interior margin of sponge implants, correlating to increased cellular density and an altered birefringence patterns. In conclusion, 10 nM dsODN decoy therapy reduced collagen deposition and altered the organization of granulation tissue, supporting its potential as a localized anti-fibrotic therapy for limiting fibrotic conditions.

Improved bioengineered cartilage tissue formation following cyclic compression is dependent on upregulation of MT1-MMP

The generation of bioengineered cartilage tissue suitable for transplantation is a potential therapy to treat damaged cartilage. We have shown previously that the physical and biomechanical properties of bioengineered cartilage can be improved by the application of 30 min of cyclic compression by a mechanism involving sequential upregulation of gene and protein levels of membrane type-1 matrix metalloproteinase (MT1-MMP) and MMP-13. In the current study, we demonstrated that MT1-MMP is critical to this response, as blocking the upregulation of MT1-MMP prevented the improvement in tissue formation. MT1-MMP seems to act by inducing tissue remodeling as evidenced by the presence of aggrecan degradation products by Western blot analysis and increased release of matrix molecules into the media. Release of these molecules was diminished when MT1-MMP upregulation was prevented. This matrix degradation was likely due to MT1-MMP, as under conditions where MMP-13 expression is maintained (stimulation in the presence of MT1-MMP siRNA) the release of these matrix molecules into the media was still prevented. It also appears that MT1-MMP does not regulate MMP-13 gene expression, as MT1-MMP-siRNA pretreatment had no effect on MMP-13 expression following mechanical stimulation. Further analysis of the anabolic genes and proteins involved in mechanically stimulated cartilage will lead to better understanding of the mechanism(s) underlying tissue formation yielding improved bioengineered cartilage.

Oligodeoxynucleotide decoy therapy blocks type 1 procollagen transcription and the prolyl hydroxylase beta subunit translation

Persistent transforming growth factor-beta1 (TGF-beta1) exposure to lungs increases type 1 collagen synthesis and deposition resulting in excess fibrosis which leads to morbidity and possibly death. We now report using human embryonic lung fibroblasts in the presence of TGF-beta1, a novel double-stranded (ds) DNA decoy with phosphorothioate (PT) linkages, containing the TGF-beta cis-element found in the distal promoter region of the COL1A1 gene which silences COL1A1 gene expression. In a cell-free protein translation system, we have previously reported that collagen synthesis was inhibited by disulfide isomerase, the prolyl-4-hydroxylase (P-4-H) beta subunit. By comparative proteomics dsdecoy therapy increased the levels of disulfide isomerase, the P-4-H beta subunit. These findings taken together support the notion that the dsdecoy inhibits type 1 collagen synthesis at both the transcriptional and translational levels.

Pericellular matrix formation alters the efficiency of intracellular uptake of oligonucleotides in osteosarcoma cells

One of the crucial roles of tumor extracellular matrix is to act as a barrier to drug delivery. In this study, we analyzed the relationship between the formation of tumor extracellular matrix and the efficiency of intracellular uptake of oligonucleotides in human osteosarcoma cell lines, HOS, and MG-63. Oligonucleotides used in this study were nuclear factor-kappa B (NF-kappaB) decoy, which might be a therapeutic tool for neoplasms. Pericellular matrix formation was examined by particle exclusion assay. Cellular uptake of fluorescein isothiocyanate-labeled NF-kappaB decoy was evaluated by fluorescent microscopy and flow cytometry. Effects of NF-kappaB decoy on cell viability and cell cycle arrest in MG-63 cells were determined by MTT assay and flow cytometry, respectively. MG-63 cells exhibited abundant pericellular matrix with time compared with HOS cells. Uptake of fluorescein isothiocyanate-labeled NF-kappaB decoy decreased in MG-63 cells with time but not in HOS cells in both monolayer and three-dimensional culture using matrigel. However, after enzymatic removal of pericellular matrix, the uptake markedly recovered in MG-63 cells. NF-kappaB decoy inhibited cell proliferation and induced G0/G1 cell cycle arrest in MG-63 cells. These results suggest that abundant pericellular matrix might disturb the uptake of NF-kappaB decoy, and modification of pericellular matrix composition would increase the efficacy of exogenous oligonucleotides treatment for neoplasms.

TGF-beta-induced fibrosis and SMAD signaling: oligo decoys as natural therapeutics for inhibition of tissue fibrosis and scarring

Transforming-growth factor-beta (TGF-beta) is a pleiotrophic growth factor that is synthesized by many cells in the body. This growth factor is chemotactic for fibroblasts, stimulates fibroblast proliferation, and increases the synthesis of a number of extracellular matrix proteins including collagens. The TGF-beta activator protein is a transacting factor, which binds to the TGF-beta element in the distal promoter of the COL1A1 collagen gene and induces transcription of this gene. Although transient TGF-beta 1 activity participates in repair and regeneration of tissues, persistent TGF-beta 1 function affects excessive fibrosis and ultimately scarring of both skin and internal organs. Scarring of internal organ (e.g., liver and lung) results in a loss of function and ultimately death may occur. The central issue of this review is that phosphorothioate double-stranded decoys or other decoys decrease procollagen gene expression, procollagen synthesis, and collagen during fibrogenesis. The rationale is that the decoys containing the TGF-beta element or other gene transcription regulatory CIS-elements bind the transacting proteins preventing the latter from binding to the CIS-element in the 5'-flanking region of the natural gene resulting in transcription inhibition. We will, in part, focus on aspects involved in TGF-beta 1-induced fibrosis that occur during fibrogenesis and the use of the dsTGF-beta element containing oligodeoxynucleotide decoys to control excessive collagen synthesis, and deposition resulting from persistent TGF-beta. In our model of regulation of collagen synthesis, these double-stranded oligo decoys act as promoter competitors, binding to the activator protein either in the cytoplasm or in the nucleus. The significance of the proposed studies is that these novel natural antifibrotics will mimic the effect of glucocorticoids on collagen synthesis during fibrogenesis without the unwanted side effects of these steroids. Based on our previous studies on the molecular mechanisms by which glucocorticoids selectively decrease collagen synthesis, designed phosphorothioate oligodeoxynucleotides resistant to nuclease action will mimic the effects of glucocorticoids at the molecular, cellular, and in vivo levels of collagen synthesis. However, the glucocorticoids significantly inhibit noncollagen protein synthesis. Both the single-stranded and double-stranded oligodeoxynucleotide specifically decrease collagen synthesis without an inhibitory effect on noncollagen protein synthesis. In this review, we will specifically ask if TGF-beta-induced collagen synthesis is inhibited in cell culture and in vivo by using the double-stranded oligodeoxynucleotide decoys, will this inhibit fibrogenesis and ultimately scarring?

Tissue fibrosis and carcinogenesis: divergent or successive pathways dictate multiple molecular therapeutic targets for oligo decoy therapies

The extracellular matrix (ECM) is composed of several families of macromolecular components: fibrous proteins such as collagens, type I collagen (COL1), type III collagen (COL3), fibronectin, elastin, and glycoconjugates such as proteoglycans and matrix glycoproteins. Their receptors on the cell membrane, most of which in the case of the ECM belong to the integrins, which are heterodimeric proteins composed of alpha and beta chains. COL1 is the major fibrous collagen of bone, tendon, and skin; while COL3 is the more pliable collagen of organs like liver. Focus will not only be given to the regulation of synthesis of several fibrogenic parameters but also modulation of their degradation during growth factor-induced tissue fibrosis and cancer development. Evidence will be provided that certain tissues, which undergo fibrosis, also become cancerous. Why does there exist a divergency between tissues, which undergo frank fibrosis as an endpoint, and those tissues that undergo fibrosis and subsequently are susceptible to carcinogenicity; resulting from the etiological factor(s) causing the initial injury? For example, why does a polyvinyl alcohol (PVA) sponge implant become encapsulated and filled with fibrous tissue then fibrosis tissue growth stops? Why does the subcutaneous injection of a fibrogenic growth factor cause a benign growth and incisional wounding results in fibrosis and ultimately scarring? There are many examples of tissues, which undergo fibrosis as a prerequisite to carcinogenesis. Is there a cause-effect relationship? If you block tissue fibrosis in these precancerous tissues, would you block cancer formation? What are the molecular targets for blocking fibrosis and ultimately carcinogenesis? How can oligo decoys may be used to attenuate carcinogenesis and which oligo decoys specifically attenuate fibrogenesis as a prelude to carcinogenesis? What are other molecular targets for oligo decoy therapy in carcinogenesis?

Enhancement of ultraviolet-induced apoptosis by NF-kappaB decoy oligonucleotides

BACKGROUND

A decoy strategy utilizing oligonucleotides (ODN) containing the specific binding sequence of a certain transcription factor has been developed and is considered to be a potential new class of antigene therapy. However, the application of this new therapeutic modality to skin diseases has not been fully documented.

OBJECTIVES

The aim of this work was to examine the effects of the nuclear factor (NF)-kappaB decoy ODN on UV-elicited skin change.

METHODS

Mouse keratinocyte Pam 212 cells were transfected with NF-kappaB decoy ODN to examine the effects of the decoy ODN on ultraviolet (UV) B-induced apoptosis. Tape-stripped rat dorsal skin was treated with an ointment containing NF-kappaB decoy ODN for the examination of the in vivo impact of the decoy ODN on sunburned cell (SBC) formation and UVB erythema.

RESULTS

NF-kappaB decoy ODN specifically induced apoptosis of Pam 212 cells and SBC formation was significantly enhanced by topical NF-kappaB decoy ODN ointment, while UV-induced erythema was not affected.

CONCLUSIONS

These data suggest that enhancement of UV-induced apoptosis by NF-kappaB decoy ODN may play a cancer-preventive role by further eliminating photodamaged keratinocytes.

Complexation to cationic microspheres of double-stranded peptide nucleic acid-DNA chimeras exhibiting decoy activity

The major aim of this paper was to determine whether cationic microspheres (CM), consisting of the permeable polymer Eudragit RS 100 plus the cationic surfactant dioctadecyl-dimethyl-ammonium bromide (DDAB(18)), could bind to double-stranded peptide nucleic acid PNA-DNA-PNA (PDP) chimeras exhibiting decoy activity against NF-kappaB transcription factors. Microspheres were produced by the 'solvent evaporation method' and centrifugation at 500, 1,000 and 3,000 rpm to obtain different-sized microparticles. Microsphere morphology, size and size distribution were determined by optical and electron microscopy observations. In order to determine their binding activity, double-stranded DNA-based and PDP-based decoy molecules were incubated with different amounts of microparticles in the presence of 100 ng of either (32)P-labeled DNA-DNA or DNA-PDP hybrid molecules or cold PDP-PDP hybrids. The complexes were analyzed by agarose gel electrophoresis. The resistance of (32)P-labeled DNA-DNA and DNA-PDP molecules in the presence of serum or cellular extracts was evaluated after binding to CM by gel electrophoresis analysis. DDAB(18) Eudragit RS 100 microspheres are able to bind to DNA-PDP and PDP-PDP hybrids, to deliver these molecules to target cells and to protect DNA-PDP molecules from enzymatic degradation in simulated biological fluids. In addition, when assayed in ex vivo conditions, DDAB(18) Eudragit RS 100 microspheres exhibited low toxicity. The results presented in this paper demonstrate that CM can be considered suitable formulations for pharmacogenomic therapy employing double-stranded PDP chimeras.

Gene therapy for cerebral vascular disease: update 2003

Gene therapy is a promising strategy for cerebrovascular diseases. Several genes that encode vasoactive products have been transferred via cerebrospinal fluid for the prevention of vasospasm after subarachnoid hemorrhage. Transfer of neuroprotective genes, including targeting of proinflammatory mediators, is a current strategy of gene therapy for ischemic stroke. Stimulation of growth of collateral vessels, stabilization of atherosclerotic plaques, inhibition of thrombosis, and prevention of restenosis are important objectives of gene therapy for coronary and limb arteries, but application of these approaches to carotid and intracranial arteries has received little attention. Several fundamental advances, including development of safer vectors, are needed before gene therapy achieves an important role in the treatment of cerebrovascular disease and stroke.

A double-strand decoy DNA oligomer for NF-kappaB inhibits TNFalpha-induced ICAM-1 expression in sinusoidal endothelial cells

Altered gene expression of liver sinusoidal endothelial cells (SECs) is associated with impaired immune response. Here we report that the decoy technique effectively suppresses TNFalpha-induced ICAM-1 expression in SEC. An NF-kappaB decoy (NF-kappaB31: 5(')-TGGGGACTTTCCAGTTTCTGGAAAGTCCCCA-3), which contains a consensus sequence for NF-kappaB, was complexed to PLL-g-HA [hyaluronate-grafted poly(L-lysine) copolymer] that permits transfer of exogenous DNA selectively to the SEC. The PLL-g-HA/NF-kappaB31 complex was added to the culture media of LSE cells, a human SEC-derived cell line. Then, cells were stimulated with TNFalpha (5ng/mL). PLL-g-HA/NF-kappaB31, but not control oligodeoxynucleotides having a reverse or scrambled sequence, inhibited the intranuclear localization of NF-kappaB induced by TNFalpha, with almost complete inhibition at 2.5microg/mL as DNA. NF-kappaB31 attenuated the increase in ICAM-1 mRNA as well as protein levels in LSE cells. The decoy technique in combination with PLL-g-HA may provide a novel strategy for manipulation of SEC functions.

Transcription factor decoy (TFD) in breast cancer research and treatment

Synthetic oligonucleotides have recently been the object of many investigations aimed to develop sequence-selective compounds able to modulate, either positively or negatively, transcription of eukaryotic and viral genes. Alteration of transcription could be obtained by using synthetic oligonucleotides mimicking target sites of transcription factors (the transcription factor decoy -TFD- approach). This could lead to either inhibition or activation of gene expression, depending on the biological functions of the target transcription factors. Since several transcription factors are involved in tumor onset and progression, this issue is of great interest in order to design anti-tumor compounds. In addition to oligonucleotides, peptide nucleic acids (PNA) can be proposed for the modulation of gene expression. In this respect, double-stranded PNA-DNA chimeras have been shown to be capable to exhibit strong decoy activity. In the case of treatment of breast cancer cells, decoy oligonucleotides mimicking CRE binding sites, promoter region of estrogen receptor alpha gene, NF-kB binding sites have been used with promising results. Therefore, the transcription factor decoy approach could be object of further studies to develop protocols for the treatment of breast cancer. In the future, transcription factors regulating cell cycle, hormone-dependent differentiation, tumor invasion and metastasis are expected to be suitable targets for transcription factor decoy.