An Artificial Placenta Experimental System in Sheep: Critical Issues for Successful Transition and Survival up to One Week.

OBJECTIVE: To describe the development of an artificial placenta (AP) system in sheep with learning curve and main bottlenecks to allow survival up to one week. METHODS: A total of 28 fetal sheep were transferred to an AP system at 110-115 days of gestation. The survival goal in the AP system was increased progressively in three consecutive study groups: 1-3 h (n = 8), 4-24 h (n = 10) and 48-168 h (n = 10). Duration of cannulation procedure, technical complications, pH, lactate, extracorporeal circulation (EC) circuit flows, fetal heart rate, and outcomes across experiments were compared. RESULTS: There was a progressive reduction in cannulation complications (75%, 50% and 0%, p = 0.004), improvement in initial pH (7.20 ± 0.06, 7.31 ± 0.04 and 7.33 ± 0.02, p = 0.161), and increment in the rate of experiments reaching survival goal (25%, 70% and 80%, p = 0.045). In the first two groups, cannulation accidents, air bubbles in the extracorporeal circuit, and thrombotic complications were the most common cause of AP system failure. CONCLUSIONS: Achieving a reproducible experimental setting for an AP system is extremely challenging, time- and effort-consuming, and requires a highly multidisciplinary team. As a result of the learning curve, we achieved reproducible transition and survival up to 7 days. Extended survival requires improving instrumentation with custom-designed devices.

SSEA-4 positive dental pulp stem cells from deciduous teeth and their induction to neural precursor cells.

BACKGROUND: Stage-specific embryonic antigen-4 (SSEA-4) is a marker for the identification of multipotent embryonic cells. It is also positive in neuroepithelial cells, precursor neural cells (NPC), and human dental pulp cells. The aim of this study was to evaluate the potential morphodifferentiation and histodifferentiation to NPC of SSEA-4 positive stem cells from human exfoliated deciduous teeth (SHED). METHODS: A SHED population in culture, positive to SSEA-4, was obtained by magnetic cell separation. The cells were characterized by immunohistochemistry and flow cytometry. Subsequently, a neurosphere assay was performed in a medium supplemented with basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF); afterward, cells were neurodifferenciated with a neurobasal medium. Finally, indirect immunohistochemistry was performed to identify neuronal markers. RESULTS: The morphological and histological changes in the SSEA-4 positive SHEDs were observed after induction with epidermal and fibroblast growth factors in neurobasal culture medium. At the end of induction, the markers Nestin, TuJ-1, and GFAP were identified. CONCLUSIONS: The findings show that SSEA-4 positive SHEDs have a behavior similar to neuronal precursor cells. Our findings indicate that the dental pulp of deciduous teeth is a promising source for regeneration therapies associated with neurodegenerative diseases or peripheral nerve alterations.

Antibacterial approaches in tissue engineering using metal ions and nanoparticles: From mechanisms to applications.

Bacterial infection of implanted scaffolds may have fatal consequences and, in combination with the emergence of multidrug bacterial resistance, the development of advanced antibacterial biomaterials and constructs is of great interest. Since decades ago, metals and their ions had been used to minimize bacterial infection risk and, more recently, metal-based nanomaterials, with improved antimicrobial properties, have been advocated as a novel and tunable alternative. A comprehensive review is provided on how metal ions and ion nanoparticles have the potential to decrease or eliminate unwanted bacteria. Antibacterial mechanisms such as oxidative stress induction, ion release and disruption of biomolecules are currently well accepted. However, the exact antimicrobial mechanisms of the discussed metal compounds remain poorly understood. The combination of different metal ions and surface decorations of nanoparticles will lead to synergistic effects and improved microbial killing, and allow to mitigate potential side effects to the host. Starting with a general overview of antibacterial mechanisms, we subsequently focus on specific metal ions such as silver, zinc, copper, iron and gold, and outline their distinct modes of action. Finally, we discuss the use of these metal ions and nanoparticles in tissue engineering to prevent implant failure.

Targeted inhibition of allergen-induced histamine production by neutrophils.

Histamine is a critical inflammatory mediator in allergic diseases. We showed in a previous work that neutrophils from allergic patients produce histamine in response to allergens to which the patients were sensitized. Here, we investigate the molecular mechanisms involved in this process using peripheral blood neutrophils. We challenged these cells in vitro with allergens and analyzed histamine release in the culture supernatants. We also explored the effect of common therapeutic drugs that ameliorate allergic symptoms, as well as allergen-specific immunotherapy. Additionally, we examined the expression of histidine decarboxylase and diamine oxidase, critical enzymes in the metabolism of histamine, under allergen challenge. We show that allergen-induced histamine release is dependent on the activation of the phosphoinositide 3-kinase, mitogen-activated protein kinase p38, and extracellular signal-regulated kinase 1/2 signaling pathways. We also found a contribution of the phosphatase calcineurin to lesser extent. Anti-histamines, glucocorticoids, anti-M3-muscarinic receptor antagonists, and mainly ß2 -receptor agonists abolished the allergen-dependent histamine release. Interestingly, allergen-specific immunotherapy canceled the histamine release through the downregulation of histidine decarboxylase expression. Our observations describe novel molecular mechanisms involved in the allergen-dependent histamine release by human neutrophils and provide new targets to inhibit histamine production.

Antitumor effect of adenoviruses expressing mutant non-oncogenic E7 versions from HPV-16 fused to calreticulin.

PURPOSE: To compare the antitumor effect of adenoviruses that express mutant variants of the protein E7 from HPV-16 fused to calreticulin. METHODS: Recombinant adenoviruses were generated to express calreticulin fused to mutant versions of E7 (CRT/E7m and CRT/E7dm). Western blot and immunofluorescence assays were made to demonstrate protein expression. Antitumor assays were performed in C57BL6 mice injected with TC-1 cell line. RESULTS: When HEK293 cells were infected with these adenoviruses, we detected that all the recombinant proteins were expressed at endoplasmic reticulum, as expected. Next, the antitumor effect was tested on a murine tumor model established by inoculation of TC-1 cell line. We detected that both Ad CRT/E7m and Ad CRT/E7dm were capable of reducing the antitumor volume when compared to Ad LacZ, which was used as negative control. No significant difference was observed when compared to Ad CRT/E7, a positive control. CONCLUSIONS: Here we demonstrated that the mutant versions of E7 HPV-16 fused to calreticulin generate similar antitumor effect than the wild type version.

Targeting HPV-16 antigens to the endoplasmic reticulum induces an endoplasmic reticulum stress response.

Very promising results have been observed with a deoxyribonucleic acid (DNA) vaccine based on human papillomavirus type-16 (HPV-16) antigen retention and delivery system in the endoplasmic reticulum (ER). However, the mechanism by which these antigens are processed once they reach this organelle is still unknown. Therefore, we evaluated whether this system awakens a stress response in the ER. Different DNA constructs based on E6 and E7 mutant antigens fused to an ER signal peptide (SP), a signal for retention in the ER (KDEL), or both signals (SPK), were transfected into HEK-293 cells. Overexpression of E6 and E7 antigens targeted to the ER (SP, and SPK constructs) induced ER stress, which was indicated by an increase of the ER-stress markers GRP78/BiP and CHOP. Additionally, the ER stress response was mediated by the ATF4 transcription factor, which was translocated into the nucleus. Besides, the overexpressed antigens were degraded by the proteasome. Through a cycloheximide-chase assay, we demonstrated that when both protein synthesis and proteasome were inhibited, the overexpressed antigens were degraded. Interestingly, when proteasome was blocked autophagy was increased and the ER stress response decreased. Taken together, these results indicate that the antigens are initially degraded by the ERAD pathway, and autophagy degradation pathway can be induced to compensate the proteasome inhibition. Therefore, we provided a new insight into the mechanism by which E6 and E7 mutant antigens are processed once they reach the ER, which will help to improve the development of more effective vaccines against cancer.

Epidermal growth factor enhances osteogenic differentiation of dental pulp stem cells in vitro.

INTRODUCTION: Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) play an important role in extracellular matrix mineralization, a complex process required for proper bone regeneration, one of the biggest challenges in dentistry. The purpose of this study was to evaluate the osteogenic potential of EGF and bFGF on dental pulp stem cells (DPSCs). MATERIAL AND METHODS: Human DPSCs were isolated using CD105 magnetic microbeads and characterized by flow cytometry. To induce osteoblast differentiation, the cells were cultured in osteogenic medium supplemented with EGF or bFGF at a low concentration. Cell morphology and expression of CD146 and CD10 surface markers were analyzed using fluorescence microscopy. To measure mineralization, an alizarin red S assay was performed and typical markers of osteoblastic phenotype were evaluated by RT-PCR. RESULTS: EGF treatment induced morphological changes and suppression of CD146 and CD10 markers. Additionally, the cells were capable of producing calcium deposits and increasing the mRNA expression to alkaline phosphatase (ALP) and osteocalcin (OCN) in relation to control groups (p < 0.001). However, bFGF treatment showed an inhibitory effect. CONCLUSION: These data suggests that DPSCs in combination with EGF could be an effective stem cell-based therapy for bone tissue engineering applications in periodontics and oral implantology.

CXCL10/XCL1 fusokine elicits in vitro and in vivo chemotaxis.

Fusokines are proteins formed by the fusion of two cytokines. They have greater bioavailability and therapeutic potential than individual cytokines or a combination of different cytokines. Interferon-gamma-inducible protein 10 (CXCL10) and lymphotactin (XCL1) are members of the chemotactic family of cytokines, which induce tumor regression by eliciting immune-system cell chemotaxis. We engineered a replication-deficient adenoviral system expressing CXCL10/XCL1 fusokine (Ad FIL) and assessed its chemotactic response in vitro and in vivo. The CXCL10/XCL1 fusokine elicited a greater chemotactic effect in IL-2 stimulated lymphocytes than individual or combined cytokines in vitro. CXCL10/XCL1 fusokine biological activity was demonstrated in vivo by intratumoral chemoattraction of CXCR3+ cells. Thus, this novel CXCL10/XCL1 fusokine may represent a potential tool for gene therapy treatment of cancer and other illnesses that require triggering immune-system cell recruitment.

Bisphosphonates inhibit stellate cell activity and enhance antitumor effects of nanoparticle albumin-bound paclitaxel in pancreatic ductal adenocarcinoma.

Pancreatic stellate cells (PSC) have been recognized as the principal cells responsible for the production of fibrosis in pancreatic ductal adenocarcinoma (PDAC). Recently, PSCs have been noted to share characteristics with cells of monocyte-macrophage lineage (MML cells). Thus, we tested whether PSCs could be targeted with the nitrogen-containing bisphosphonates (NBP; pamidronate or zoledronic acid), which are potent MML cell inhibitors. In addition, we tested NBPs treatment combination with nanoparticle albumin-bound paclitaxel (nab-paclitaxel) to enhance antitumor activity. In vitro, we observed that PSCs possess α-naphthyl butyrate esterase (ANBE) enzyme activity, a specific marker of MML cells. Moreover, NBPs inhibited PSCs proliferation, activation, release of macrophage chemoattractant protein-1 (MCP-1), and type I collagen expression. NBPs also induced PSCs apoptosis and cell-cycle arrest in the G1 phase. In vivo, NBPs inactivated PSCs; reduced fibrosis; inhibited tumor volume, tumor weight, peritoneal dissemination, angiogenesis, and cell proliferation; and increased apoptosis in an orthotopic murine model of PDAC. These in vivo antitumor effects were enhanced when NBPs were combined with nab-paclitaxel but not gemcitabine. Our study suggests that targeting PSCs and tumor cells with NBPs in combination with nab-paclitaxel may be a novel therapeutic approach to PDAC.

Bacteriemia por Listeria monocytogenes / Bacteremia for Listeria monocytogenes

Se realiza un estudio en el Laboratorio de Microbiología del Centro Provincial de Higiene de Guantánamo, del 23 al 30 de mayo de 2011, con el objetivo de identificar el agente etiológico de bacteriemia en un paciente con insuficiencia renal. El universo de estudio estuvo formado por una cepa procedente del Laboratorio de Microbiología del Hospital General Docente de Guantánamo, aislada de un hemocultivo, a la que se le realizaron diferentes pruebas para su identificación. La cepa se identifica como Listeria monocytogenes. Se describen las características morfológicas, culturales, bioquímicas y se realizó antibiograma por el método de Kirby Bauer, informando al hospital, donde el paciente tuvo una evolución satisfactoria. Se concluye sobre la importancia de la correcta limpieza de los vegetales previo al consumo y ser oportunos en el estudio microbiológico ante la sospecha de sepsis(AU)

A study is done in the Laboratory of Microbiology of the Provincial Center of Hygiene of Guantanamo, from May 23 to May 30, 2011, with the target to identify the etilogical agent of bacteremia in a patient with renal insufficiency. The studied universe was formed by a stump proceeding from the Laboratory of Microbiology of the Hospital Guantanamo, isolated of a culture, to whom different tests were done for its identification. The stump is identified as Listeria monocytogenes. The morphologic, cultural, biochemical characteristics are described and it was done antibiotic tests by the method of Kirby Bauer, reporting to the hospital, where the patient had a satisfactory evolution. It ends on the importance of the correct cleanliness of the vegetables before the consumption and to be opportune in the microbiological study before the sepsis suspicion

Cyclooxygenase-2 utilizes Jun N-terminal kinases to induce invasion, but not tamoxifen resistance, in MCF-7 breast cancer cells.

Elevated cyclooxygenase-2 (COX-2) expression in breast tumors is associated with a lower survival rate in patients with estrogen receptor α (ERα)-positive tumors. We hypothesized that COX-2 reduces the survival rate of breast cancer patients with ERα-positive tumors since COX-2 increases the invasiveness of ERα-positive breast tumors and decreases tumor sensitivity to tamoxifen. Previously, we demonstrated that COX-2 stimulates the activity of protein kinase C (PKC) to increase the invasiveness of ERα-positive MCF-7 breast cancer cells and to decrease the sensitivity of MCF-7 cells to tamoxifen. High levels of COX-2 are associated with the activation of the mitogen-activated protein kinase (MAPK) family and the Akt kinase. However, it is not known whether these kinases mediate COX-2-induced invasive activity and tamoxifen resistance. In the present study, we report that COX-2 utilizes PKC to enhance the phosphorylation of Jun N-terminal kinases (JNKs), but not that of other MAPK family members or Akt. Inhibition aimed at JNKs reduced COX-2-induced invasion but not COX-2-induced tamoxifen resistance. We conclude that JNKs are essential for induced cell invasion by COX-2, but not tamoxifen resistance, in ERα-positive breast cancer cells.

Programmed cell death 4 inhibits leptin-induced breast cancer cell invasion.

Obesity is a significant risk factor for post-menopausal women to develop and die from breast cancer. Leptin, an adipokine is produced in high levels in obese individuals, and its receptor is overexpressed in breast tumors and lymph node metastases. Previously, we demonstrated that leptin stimulates breast cancer cell invasion, which is correlated with breast cancer metastasis. Programmed cell death 4 (PDCD4) has been shown to block cancer cell invasion. However, whether PDCD4 blocks leptin-induced breast cancer cell invasion is not known. Here, we report the novel findings that leptin failed to induce invasion in MCF-7 breast cancer cells overexpressing PDCD4 (MCF-7/PDCD4). Tissue inhibitor of metalloproteinase-2 (TIMP-2) was essential to the anti-invasive effect of PDCD4, as leptin stimulated the invasion of MCF-7/PDCD4 cells pretreated with TIMP-2 siRNA. Furthermore, TIMP-2 knockdown allowed leptin to augment phosphorylation of extracellular signal-regulated kinases 1,2 and signal transducer and activator of transcription 3, but not that of Jun N-terminal kinases. These data indicate that PDCD4 utilizes TIMP-2 to exert its anti-invasive effect by suppressing leptin-induced activation of extracellular signal-regulated kinases 1,2 and signal transducer and activator of transcription 3. Novel therapeutic strategies aiming at enhancing PDCD4 expression in breast tumors may be able to stop obesity-related breast tumor progression and prolong the life of patients.

Intervención educativa sobre infecciones de transmisión sexual en adolescentes de Venezuela / Educational intervention on sexually transmitted infections among adolescents in Venezuela

Se realiza una intervención educativa en adolescentes de Barrio Bicentenario II, parroquia Miguel Peña, en el período mayo de 2006 a enero de 2007 para modificar conocimientos sobre infecciones de transmisión sexual (ITS). De 250 adolescentes, se seleccionaron 90 por muestreo aleatorio, inicialmente se confecciona un cuestionario con las variables edad, sexo, conocimientos de la enfermedad, prevención y uso correcto del condón, aplicándose antes de la intervención, luego se realizan actividades educativas con los grupos formados; aplicándose nuevamente dicho cuestionario 6 meses después de finalizada la intervención, determinándose que inicialmente, los adolescentes tenían conocimientos inadecuados y después de la intervención mejoraron sus conocimientos. Se concluye que el bajo nivel de conocimientos está relacionado con insuficientes actividades educativas realizadas en el barrio, demostrándose que esta intervención resulta eficaz en el aporte de conocimientos a los adolescentes, se recomienda aumentar las acciones de salud en cuanto al conocimiento de las ITS (AU)

An educational intervention in adolescents, Bicentennial Quarter II, parish Miguel Pena, Venezuela is done, from May 2006 to January 2007 to modify knowledge about sexually transmitted infections (STIs). A sample 250 adolescents, but 90 teenagers were selected by random. Initially was drawn up a questionnaire with the following variables: age, sex, knowledge of disease, prevention and correct condom use, applying before the intervention, also educational activities with the formed groups, applying again the questionnaire, six months after finishing the intervention .previously , adolescents had inadequate knowledge and after the intervention improved their knowledge. As a conclusion, low level of knowledge is related to insufficient educational activities in the neighborhood, showing that this intervention was effective in providing knowledge to adolescents; it is recommended to increase health actions in the knowledge of STIs

Production of biologically active human lymphotactin (XCL1) by Lactococcus lactis.

Lymphotactin-XCL1 is a chemokine produced mainly by activated CD8+ T-cells and directs migration of CD4+ and CD8+ lymphocytes and natural killer (NK) cells. We expressed human lymphotactin (LTN) by the lactic-acid bacterium Lactococcus lactis. Biological activity of LTN was confirmed by chemo-attraction of human T-cells by chemotaxis demonstrating, for the first time, how this chemokine secreted by a food-grade prokaryote retains biological activity and chemoattracts T lymphocytes. This strain thus represents a feasible well-tolerated vector to deliver active LTN at a mucosal level.

Secretion of biologically active interferon-gamma inducible protein-10 (IP-10) by Lactococcus lactis.

BACKGROUND: Chemokines are a large group of chemotactic cytokines that regulate and direct migration of leukocytes, activate inflammatory responses, and are involved in many other functions including regulation of tumor development. Interferon-gamma inducible-protein-10 (IP-10) is a member of the C-X-C subfamily of the chemokine family of cytokines. IP-10 specifically chemoattracts activated T lymphocytes, monocytes, and NK cells. IP-10 has been described also as a modulator of other antitumor cytokines. These properties make IP-10 a novel therapeutic molecule for the treatment of chronic and infectious diseases. Currently there are no suitable live biological systems to produce and secrete IP-10. Lactococcus lactis has been well-characterized over the years as a safe microorganism to produce heterologous proteins and to be used as a safe, live vaccine to deliver antigens and cytokines of interest. Here we report a recombinant strain of L. lactis genetically modified to produce and secrete biologically active IP-10. RESULTS: The IP-10 coding region was isolated from human cDNA and cloned into an L. lactis expression plasmid under the regulation of the pNis promoter. By fusion to the usp45 secretion signal, IP-10 was addressed out of the cell. Western blot analysis demonstrated that recombinant strains of L. lactis secrete IP-10 into the culture medium. Neither degradation nor incomplete forms of IP-10 were detected in the cell or supernatant fractions of L. lactis. In addition, we demonstrated that the NICE (nisin-controlled gene expression) system was able to express IP-10 "de novo" even two hours after nisin removal. This human IP-10 protein secreted by L. lactis was biological active as demonstrated by Chemotaxis assay over human CD3+T lymphocytes. CONCLUSION: Expression and secretion of mature IP-10 was efficiently achieved by L. lactis forming an effective system to produce IP-10. This recombinant IP-10 is biologically active as demonstrated by its ability to chemoattract human CD3+ T lymphocytes. This strain of recombinant L. lactis represents a potentially useful tool to be used as a live vaccine in vivo.

Liposome-incorporated Grb2 antisense oligodeoxynucleotide increases the survival of mice bearing bcr-abl-positive leukemia xenografts.

We previously demonstrated that liposome-incorporated antisense oligodeoxynucleotide specific for the grb2 mRNA (L-Grb2) inhibited Grb2 protein expression and the proliferation of bcr-abl-positive leukemia cell lines. To determine whether L-Grb2 has the potential of being a therapeutic modality against bcr-abl-positive leukemia, we studied the tissue distribution of L-Grb2 in normal mice before studying its effects in mice bearing bcr-abl-positive leukemia xenografts. L-Grb2 was widely distributed in the body. The highest tissue concentrations of L-Grb2 were found in the spleen and liver, which are the organs where the tumor mass of bcr-abl-positive leukemia is mainly found. At 4 h post-injection, the amount of L-Grb2 detected per g of tissue was 64 microg in spleen and 50 microg in liver. Intravenous injection of bcr-abl-positive 32D mouse leukemia cells into radiated NOD/scid mice caused a lethal leukemia syndrome; we determined whether L-Grb2 could prolong the survival of mice bearing such xenografts. One day after leukemia cell inoculation, mice received twice weekly intravenous injections of L-Grb2. At an injection dose of 15 mg of L-Grb2 per kg of mouse body weight, 80% of mice treated with L-Grb2 survived to 48 days (end of study) whereas 0% of mice treated with the same dose of liposomal control oligonucleotide survived; the mean survival duration of these groups was 44 and 20 days, respectively. Our data indicate that L-Grb2 prolonged the survival of mice bearing bcr-abl-positive leukemia xenografts. L-Grb2 may be used as a novel cancer therapeutic modality.

Cyclooxygenase-2 protein reduces tamoxifen and N-(4-hydroxyphenyl)retinamide inhibitory effects in breast cancer cells.

Approximately 30-40% of estrogen receptor alpha (ERalpha)-positive breast tumors express high levels of the cyclooxygenase-2 (COX-2) protein, and these high levels have been associated with a poorer prognosis in breast cancer patients. We speculate that high levels of COX-2 induce drug resistance in ERalpha-positive breast tumors, thus reducing the survival rate of patients with such tumors. Human breast cancer cell lines that express high levels of COX-2 are generally ERalpha negative. To determine whether COX-2 induces drug resistance, plasmids encoding the COX-2 gene were stably transfected into ERalpha-positive MCF-7 human breast cancer cells (MCF-7/COX-2). MCF-7/COX-2 cells were resistant to the selective estrogen receptor modulator tamoxifen but not to its analog, raloxifene. MCF-7/COX-2 cells were also resistant to the retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) but not to its analog, all-trans retinoic acid. In contrast, the sensitivities of MCF-7/COX-2 cells to doxorubicin and paclitaxel were similar to those of the parental MCF-7 cells. We then determined which COX-2 product, prostaglandin E2 (PGE2) or prostaglandin F2alpha is involved in the COX-2-mediated drug resistance. PGE2, but not PGF2alpha, blocked the antiproliferative effects of tamoxifen and 4-HPR. Agonists that activate PGE2 receptors and their downstream kinase effectors, protein kinases A and C, also blocked the growth inhibitory effects of these drugs. Increased levels of Bcl-2 and Bcl-XL proteins have been reported in mammary tumors of COX-2 transgenic mice and in human colon cancer cell lines that have high levels of COX-2. However, we did not observe any changes in Bcl-2, Bcl-XL, or Bax expression induced by COX-2 or PGE2. Here we report the novel findings that COX-2 uses PGE2 to stimulate the activities of protein kinases A and C to induce selectively tamoxifen and 4-HPR resistance in ERalpha-positive breast cancer cells.

Cellular pharmacology of P-ethoxy antisense oligonucleotides targeted to Bcl-2 in a follicular lymphoma cell line.

A P-ethoxy oligonucleotide (oligo), 20 bases long and specific for the translation initiation site of human Bcl-2 mRNA, was incorporated into liposomes to increase its intracellular delivery. This oligo selectively inhibited Bcl-2 protein expression and induced growth inhibition in t(14;18)-positive transformed follicular lymphoma (FL) cell lines. We studied the inhibitory effects of shorter liposomal P-ethoxy oligos (7, 9, 11 or 15 mer) in order to determine the activity of different oligo chain lengths targeted to the same Bcl-2 mRNA. At 12 microM, all the oligos inhibited the growth of a FL cell line. We compared the 7-mer oligo with the 20-mer oligo. The two oligos inhibited Bcl-2 protein expression similarly: 66% and 60% for the 7- and 20-mer, respectively. The uptake and retention of both oligos were also very similar. Our results indicate that the Bcl-2 inhibitory activity is maintained with P-ethoxy antisense oligos ranging from 7 to 20 bases.

Bcl-2-related antisense therapy.

High expression of the bcl-2 proto-oncogene is found in various human hematologic malignancies and solid tumors. Bcl-2 protein exerts its oncogenic role by preventing tumor cells from undergoing apoptosis induced by radiation, chemotherapy, and hormonal therapy. Antisense oligonucleotides directed toward the open reading frame of the bcl-2 gene have been used to inhibit Bcl-2 expression. Inhibition of Bcl-2 expression sensitizes lymphoma and leukemia cells to radiation and chemotherapy. However, it remains to be determined whether Bcl-2 antisense oligonucleotides will have a beneficial effect in solid tumors, such as breast cancer. Laboratory results indicate that Bcl-2 overexpression induces endocrine and chemoresistance in breast cancer cells. However, high levels of Bcl-2 have been associated with favorable prognostic factors, suggesting that Bcl-2 may not be an appropriate target in breast cancer. We will discuss the paradoxical role of Bcl-2 and the potential therapeutic application of Bcl-2 antisense oligonucleotides in breast cancer.