82 research outputs found
Use of Gene Therapy in a Subcutaneous Murine Model of Lung Cancer
OBJECTIVE: To assess the effectiveness of in vivo gene
therapy to treat subcutaneous tumors generated from murine
lung cancer cells.
MATERIAL AND METHODS: C57BL/6 mice received
subcutaneus injections of 5×105 cells from the murine Lewis
lung cancer cell line. By 10 days, subcutaneous tumors of
approximately 5 mm diameter were formed. At that point,
treatment was provided by intratumor injection of a
replication-defective recombinant adenovirus carrying the
gene for thymidine kinase (AdCMV-Tk) or interleukin (IL)
12 (AdCMV-IL12), or by injection of syngeneic dendritic
cells previously transduced with adenovirus containing the
IL-12 gene (DC-IL12). Control groups were treated with
saline or adenovirus containing the gene for β-galactosidase
(AdCMV-LacZ), which functions as a reporter gene and
does not have a therapeutic effect. The number of animals in
each group ranged from 14 to 25 in experiments using
adenovirus and from 10 to 12 in experiments using dendritic
cells. Tumor size was followed for 3 weeks in the case of
treatment with adenovirus and 4 weeks for treatment with
dendritic cells.
RESULTS: A significant reduction in subcutaneous tumor
growth was observed in the groups treated with AdCMVTk,
AdCMV-IL12, and DC-IL12 compared with control
groups treated with saline or AdCMV-LacZ. The difference
was statistically significant from day 7 of treatment in the
AdCMV-Tk group, from day 9 in the AdCMV-IL12 group,
and from day 10 in the DC-IL12 group, and in all cases it
was maintained until the end of the follow-up period.
CONCLUSIONS: Gene therapy with AdCMV-Tk, AdCMVIL12,
or DC-IL12 is effective in our model of subcutaneous
tumors arising from cells of the Lewis lung cancer cell line.
The treatment leads to a significant reduction in tumor
growth compared with control groups
Effect of Sex and Fat Depot Location on Fat Composition of Rasa Aragonesa Lambs
The quality of lamb fat is important in sheep carcass
markets because it affects the degree of acceptance by
consumers. In Spain, consumption of beef and lamb is
important and young lambs are highly valued. In addition,
the precocity of the female determines slaughter at younger
ages than males, to avoid excessive fat. Therefore, the effect
of sex and fat depot location (omental, mesenteric, kidney
knob, subcutaneous, intermuscular and intramuscular) on
the fatty acid composition in 30 Rasa Aragonesa lambs (15
males and 15 females) of 24 kg live weight and three months
of age, were studied. Oleic, palmitic and stearic fatty acids
were the main fatty acids making up the fat in all the fat
depots from lambs. There were no significant differences
(p0.05) in the fat composition between male and female
lambs, even though females had significantly more fat than
males in all the fat depots considered (p0.05). Criteria
associated with sex did not affect the composition of fat.
Ratio of fatty acids n-6/n-3 values were in the range of
recommended average values (4), except for intramuscular
fat, where values marginally higher were observed (5.5).
The internal (omental, mesenteric and kidney knob) fat
depots contained more saturated fatty acids than the edibles
depots (subcutaneous, intermuscular and intramuscular)
(p0.05). Consequently, the internal fat depot was firmer
than fat from the surface of the carcass. Fatty acid of
intramuscular fat depot had the highest content of PUFA of
all fat deposits studied.La calidad de la grasa de cordero es importante en los mercados de canales ovinas porque afecta al grado de aceptación
de los consumidores. En España, el consumo de carne de
res y cordero es importante, y los corderos jóvenes son muy
valorados. Además, la precocidad de las hembras determina
su sacrificio a edades más tempranas que los machos para
evitar su excesivo engrasamiento. Por tanto, se estudiaron el
efecto del sexo y del depósito de grasa (omental, mesentérica, pelvicorrenal, subcutánea, intermuscular e intramuscular) sobre la composición de ácidos grasos en 30 corderos de
raza Rasa Aragonesa (15 machos y 15 hembras) de 24 kg de
peso vivo y tres meses de edad. Los principales ácidos grasos
que componen la grasa en todos los depósitos de grasa de
los corderos fueron los ácidos oleico, palmítico y esteárico.
No hubo diferencias significativas (p0.05) en la composición de la grasa entre los corderos machos y hembras, a pesar de que las hembras presentaron significativamente más
grasa que los machos en todos los depósitos considerados
(p0.05). Los criterios asociados con el sexo no afectaron
a la composición de la grasa. La relación de ácidos grasos
n-6/n-3 se encontró en el rango de los valores promedio recomendados (4), excepto la grasa intramuscular, donde se
observaron valores más altos (5.5). Los depósitos de grasa
interna (omental, mesentérica y pelvicorrenal) mostraron
más ácidos grasos saturados que los depósitos comestibles
(subcutáneo, intermuscular e intramuscular) (p0.05). En
consecuencia, el depósito de grasa interna presentó grasa
más firme que el de la superficie de la canal. Los ácidos grasos del depósito intramuscular presentó el contenido más
alto de ácidos grasos poliinsaturados de todos los depósitos
de grasa estudiados
Upregulation of natural killer cells functions underlies the efficacy of intratumorally injected dendritic cells engineered to produce interleukin-12
OBJECTIVE:
Injection of dendritic cells (DC) engineered with recombinant adenoviral vectors to produce interleukin-12 (IL-12) inside experimental murine tumors frequently achieves complete regressions. In such a system the function of CD8(+) T cells has been shown to be an absolute requirement, in contrast to observations made upon depletion of CD4(+) T cells, which minimally affected the outcome. The aim of this work was to study the possible involvement of natural killer (NK) cells in this setting. MATERIALS, METHODS, AND
RESULTS:
Depletions with anti-AsialoGM1 antiserum showed only a small decrease in the proportion of complete regressions obtained that correlated with induction of NK activities in lymphatic tissues into which DC migrate, whereas combined depletions of CD4(+) and NK cells completely eliminated the antitumor effects. Likewise in vivo neutralization of interferon-gamma (IFN-gamma) also eliminated those therapeutic effects. Trying to define the cellular role played by NK cells in vivo, it was observed that injection of cultured DC inside the spleen of T- and B-cell-deficient (Rag1(-/-)) mice induced upregulation of NK activity only if DC had been adenovirally engineered to produce IL-12. In addition, identically transfected fibroblasts also activated NK cells, indicating that IL-12 transfection was the unique requirement. Equivalent human DC only activated in vitro the cytolytic and cytokine-secreting functions of autologous NK cells if transfected to express human IL-12.
CONCLUSIONS:
Overall, these results point out an important role played by NK cell activation in the potent immunotherapeutic effects elicited by intratumoral injection of IL-12--secreting DC and that NK activation under these conditions is mainly, if not only, dependent on IL-12
Improving efficacy of interleukin-12-transfected dendritic cells injected into murine colon cancer with anti-CD137 monoclonal antibodies and alloantigens
Intralesional administration of cultured dendritic cells (DCs) engineered to produce IL-12 by in vitro infection with recombinant adenovirus frequently displays eradicating efficacy against established subcutaneous tumors derived from the CT26 murine colon carcinoma cell line. The elicited response is mainly mediated by cytolytic T lymphocytes. In order to search for strategies that would enhance the efficacy of the therapeutic procedure against less immunogenic tumors, we moved onto malignancies derived from the inoculation of MC38 colon cancer cells that are less prone to undergo complete regression upon a single intratumoral injection of IL-12-secreting DCs. In this model, we found that repeated injections of such DCs, as opposed to a single injection, achieved better efficacy against both the injected and a distantly implanted tumor; that the use of semiallogeneic DCs that are mismatched in one MHC haplotype with the tumor host showed slightly better efficacy; and that the combination of this treatment with systemic injections of immunostimulatory anti-CD137 (4-1BB) monoclonal antibody achieved potent combined effects that correlated with the antitumor immune response measured in IFN-gamma ELISPOT assays. The elicited systemic immune response eradicates concomitant untreated lesions in most cases. Curative efficacy was also found against some tumors established for 2 weeks when these strategies were used in combination. These are preclinical pieces of evidence to be considered in order to enhance the therapeutic benefit of a strategy that is currently being tested in clinical trials. Supplementary Material for this article can be found on the International Journal of Cancer website at http://www.interscience.wiley.com/jpages/0020-7136/suppmat/index.html
Anti-ICAM-2 monoclonal antibody synergizes with intratumor gene transfer of interleukin-12 inhibiting activation-induced T-cell death
PURPOSE:
Systemic treatment with an anti-ICAM-2 monoclonal antibody (mAb; EOL4G8) eradicates certain established mouse tumors through a mechanism dependent on the potentiation of a CTL-mediated response. However, well-established tumors derived from the MC38 colon carcinoma cell line were largely refractory to this treatment as well as to intratumor injection of a recombinant adenovirus encoding interleukin-12 (IL-12; AdCMVIL-12). We sought to design combined therapy strategies with AdCMVIL-12 plus anti-ICAM-2 mAbs and to identify their mechanism of action.
EXPERIMENTAL DESIGN:
Analysis of antitumor and toxic effects were performed with C57BL/6 mice bearing established MC38 tumors. Anti-ovalbumin T-cell receptor transgenic mice and tumors transfected with this antigen were used for in vitro and in vivo studies on activation-induced cell death (AICD) of CD8(+) T cells.
RESULTS:
Combined treatment with various systemic doses of EOL4G8 mAb plus intratumor injection of AdCMVIL-12 induced complete regression of MC38 tumors treated 7 days after implantation. Unfortunately, most of such mice succumbed to a systemic inflammatory syndrome that could be prevented if IFN-gamma activity were neutralized once tumors had been rejected. Importantly, dose reduction of EOL4G8 mAb opened a therapeutic window (complete cure of 9 of 18 cases without toxicity). We also show that ICAM-2 ligation by EOL4G8 mAb on activated CTLs prevents AICD, thus extending IFN-gamma production.
CONCLUSIONS:
Combination of intratumor gene transfer of IL-12and systemic anti-ICAM-2 mAb display synergistic therapeutic and toxic effects. CTL life extension resulting from AICD inhibition by anti-ICAM-2 mAbs is the plausible mechanism of action
Potentiation of therapeutic immune responses against malignancies with monoclonal antibodies
Immunotherapeutic monoclonal antibodies (mAbs) can be
defined as those that exert their functions by tampering with
immune system cell molecules, causing an enhancement of
antitumor immune responses. Some of these antibodies are
agonistic ligands for surface receptors involved in the activation
of lymphocytes and/or antigen-presenting cells, whereas
others are antagonists of mechanisms that normally limit the
intensity of immune reactions. Several mAbs of this category
have been described to display in vivo antitumor activity in
mouse models. Only anti–CTLA-4 (CD152) mAb has entered
clinical trials, but the preclinical effects described for anti-
CD40, anti-CD137 (4-1BB), anti-CD102 (intercellular adhesion
molecule-2), and regulatory T cell-depleting mAbs should lead
to their prompt clinical development. Their use in combination
with immunizations against tumor antigens has been reported
to be endowed with synergistic properties. This new group of
antitumor agents holds promise for at least additive effects with
conventional therapies of cancer and deserves intensive translational
research
An anti-ICAM-2 (CD102) monoclonal antibody induces immune-mediated regressions of transplanted ICAM-2-negative colon carcinomas
Monoclonal antibodies (mAbs) can mediate antitumor effects by indirect mechanisms involving antiangiogenesis and up-regulation of the cellular immune response rather than by direct tumor cell destruction. From mAbs raised by immunization of rats with transformed murine endothelial cells, a mAb (EOL4G8) was selected for its ability to eradicate a fraction of established colon carcinomas that did not express the EOL4G8-recognized antigen. The antigen was found to be ICAM-2 (CD102). Antitumor effects of EOL4G8, which required a functional T-cell compartment, were abrogated by depletion of CD8(+) cells and correlated with antitumor CTL activity, whereas only a mild inhibition of angiogenesis was observed. Interestingly, we found that EOL4G8 acting on endothelial ICAM-2 markedly enhances leukotactic factor activity-1-independent adhesion of immature dendritic cells to endothelium-an effect that is at least in part mediated by DC-SIGN (CD209)
The immunotherapy potential of agonistic anti-CD137 (4-1BB) monoclonal antibodies for malignancies and chronic viral diseases
Pharmacological intervention on the immune system to
achieve more intense lymphocyte responses has potential application
in tumour immunology and in the treatment of chronic
viral diseases. Immunostimulating monoclonal antibodies are
defined as a new family of drugs that augment cellular immune
responses. They interact as artificial ligands with functional proteins
of the immune system, either activating or inhibiting their
functions. There are humanized monoclonal antibodies directed
to the inhibitory receptor CD152 (CTLA-4) that are being tested
in clinical trials with evidence of antitumoural activity. As a
drawback, anti-CTLA-4 monoclonal antibodies induce severe
autoimmunity reactions in a fraction of the patients. Anti-CD137
monoclonal antibodies have the ability to induce potent
immune responses mainly mediated by cytotoxic lymphocytes
with the result of frequent complete tumour eradications in
mice. Comparative studies in experimental models indicate that
the antitumour activity of anti-CD137 monoclonal antibodies is
superior to that of anti-CD152. CD137 (4-1BB) is a leukocyte differentiation
antigen selectively expressed on the surface of activated
T and NK lymphocytes, as well as on dendritic cells. Monoclonal
antibodies acting as artificial stimulatory ligands of this
receptor (anti-CD137 agonist antibodies) enhance cellular antitumoural
and antiviral immunity in a variety of mouse models.
Paradoxically, anti-CD137 monoclonal antibodies are therapeutic
or preventive in the course of model autoimmune diseases in
mice. In light of these experimental results, a number of
research groups have humanized antibodies against human
CD137 and early clinical trials are about to start
Dendritic cells delivered inside human carcinomas are sequestered by interleukin-8
In the course of a clinical trial consisting of intratumoral injections of dendritic cells (DCs) transfected to produce interleukin-12, the use of (111)In-labeled tracing doses of DCs showed that most DCs remained inside tumor tissue, instead of migrating out. In search for factors that could explain this retention, it was found that tumors from patients suffering hepatocellular carcinoma, colorectal or pancreatic cancer were producing IL-8 and that this chemokine attracted monocyte-derived dendritic cells that uniformly express both IL-8 receptors CXCR1 and CXCR2. Accordingly, neutralizing antihuman IL-8 monoclonal antibodies blocked the chemotactic attraction of DCs by recombinant IL-8, as well as by the serum of the patients or culture supernatants of human colorectal carcinomas. In addition, tissue culture supernatants of colon carcinoma cells inhibited DC migration induced by MIP-3beta in an IL-8-dependent fashion. IL-8 production in malignant tissue and the responsiveness of DCs to IL-8 are a likely explanation of the clinical images, which suggest retention of DCs inside human malignant lesions. Impairment of DC migration toward lymphoid tissue could be involved in cancer immune evasion
Low surface expression of B7-1 (CD80) is an immunoescape mechanism of colon carcinoma
Artificially enforced expression of CD80 (B7-1) and CD86 (B7-2) on tumor cells renders them more immunogenic by triggering the CD28 receptor on T cells. The enigma is that such B7s interact with much higher affinity with CTLA-4 (CD152), an inhibitory receptor expressed by activated T cells. We show that unmutated CD80 is spontaneously expressed at low levels by mouse colon carcinoma cell lines and other transplantable tumor cell lines of various tissue origins. Silencing of CD80 by interfering RNA led to loss of tumorigenicity of CT26 colon carcinoma in immunocompetent mice, but not in immunodeficient Rag-/- mice. CT26 tumor cells bind CTLA-4Ig, but much more faintly with a similar CD28Ig chimeric protein, thus providing an explanation for the dominant inhibitory effects on tumor immunity displayed by CD80 at that expression level. Interestingly, CD80-negative tumor cell lines such as MC38 colon carcinoma and B16 melanoma express CD80 at dim levels during in vivo growth in syngeneic mice. Therefore, low CD80 surface expression seems to give an advantage to cancer cells against the immune system. Our findings are similar with the inhibitory role described for the dim CD80 expression on immature dendritic cells, providing an explanation for the low levels of CD80 expression described in various human malignancies
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