Three agonist antibodies in combination with high-dose IL-2 eradicate orthotopic kidney cancer in mice

<p>Abstract</p> <p>Background</p> <p>Combination immunotherapies can be effective against subcutaneous tumors in mice but the effect against orthotopic malignant disease is less well characterized. In particular, a combination of three agonist antibodies, termed Tri-mAb, consisting of anti-DR5, anti-CD40 and anti-CD137 has previously been demonstrated to eradicate a large proportion of subcutaneous renal cell carcinoma (Renca) tumors (75% long-term survival), but the effect against orthotopic disease is not known.</p> <p>Purpose</p> <p>To determine the relative response of orthotopic tumors, we inoculated Renca into the kidney followed by treatment with Tri-mAb.</p> <p>Results</p> <p>We found that orthotopic tumors responded much less to treatment (~13% survival), but a significant improvement in survival was achieved through the addition of IL-2 to the treatment regimen (55% survival). All three agonist antibodies and high dose IL-2, 100,000 IU for up to six doses, were required. CD8⁺T cells were also required for optimal anti-tumor responses. Coadministration of IL-2 led to enhanced T cell activity as demonstrated by an increased frequency of IFN-gamma-producing T cells in tumor-draining lymph nodes, which may have contributed to the observed improvement of therapy against kidney tumors.</p> <p>Implications</p> <p>Responses of subcutaneous tumors to immunotherapy do not necessarily reflect how orthotopic tumors respond. The use of combination immunotherapy stimulating multiple facets of immunity and including cytokine support for T cells can induce effective anti-tumor responses against orthotopic and metastatic tumors.</p

Sodium channel gene family: epilepsy mutations, gene interactions and modifier effects

The human sodium channel family includes seven neuronal channels that are essential for the initiation and propagation of action potentials in the CNS and PNS. In view of their critical role in neuronal firing and their strong sequence conservation during evolution, it is not surprising that mutations in the sodium channel genes are responsible for a growing spectrum of channelopathies. Nearly 700 mutations of the SCN1A gene have been identified in patients with Dravet's syndrome (severe myoclonic epilepsy of infancy), making this the most commonly mutated gene in human epilepsy. A small number of mutations have been found in SCN2A , SCN3A and SCN9A , and studies in the mouse suggest that SCN8A may also contribute to seizure disorders. Interactions between genetic variants of SCN2A and KCNQ2 in the mouse and variants of SCN1A and SCN9A in patients provide models of potential genetic modifier effects in the more common human polygenic epilepsies. New methods for generating induced pluripotent stem cells and neurons from patients will facilitate functional analysis of amino acid substitutions in channel proteins. Whole genome sequencing and exome sequencing in patients with epilepsy will soon make it possible to detect multiple variants and their interactions in the genomes of patients with seizure disorders.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79388/1/jphysiol.2010.188482.pd

CD1d activation and blockade: A new antitumor strategy

CD1d is expressed on APCs and presents glycolipids to CD1d-restricted NKT cells. For the first time, we demonstrate the ability of anti-CD1d mAbs to inhibit the growth of different CD1d-negative experimental carcinomas in mice. Anti-CD1d mAbs systemically activated CD1d APC, as measured by production of IFN-γ and IL-12. Tumor growth inhibition was found to be completely dependent on IFN-γ and IL-12 and variably dependent on CD8 T cells and NK cells, depending upon the tumor model examined. Anti-CD1d mAb induced greater CD8 T cell-dependent tumor suppression where regulatory CD1d-restricted type II NKT cells have been implicated, and were less effective in a NK cell-dependent manner against tumors where T regulatory cells were immunosuppressive. The ability of anti-CD1d mAbs to coincidently activate CD1d APCs to release IL-12 and inhibit CD1d-restricted type II NKT cells makes CD1d an exciting new target for immunotherapy of cancer based on tumor immunoregulation

CD1d-based combination therapy eradicates established tumors in mice

The use of Abs that induce tumor cell death together with immunostimulatory reagents to activate innate and adaptive immune cells has emerged as a potent approach for the treatment of cancer. We have previously demonstrated that the use of three mAbs (anti-DR5, anti-CD40, anti-CD137) termed TriMab can induce rejection in a majority of mice with established experimental or carcinogen-induced tumors. However, given the potential toxicity of CD40 agonists in the clinic, we tested an alternative approach to directly activate/mature APCs using anti-CD1d mAbs. In this study, we used a combination of three mAbs (anti-DR5, anti-CD137, anti-CD1d) that we termed 1DMab and demonstrated that this approach suppressed and/or eradicated established experimental renal, breast, and colon carcinomas in mice. Tumor suppression induced by 1DMab therapy required CD8 T cells, IFN-γ, and CD1d, while NK cells and IL-12 were partially required. Interestingly 1DMab therapy was more effective than TriMab in tumor models regulated by CD1d-restricted type II NKT cells, but less efficacious against tumors where T regulatory cells were critical. Anti-CD1d mAbs could also be relatively effective in combination with anti-CD137 and conventional chemotherapeutics. This is the first study to illustrate the antitumor activity of CD1d-reactive mAbs in combination and our results strongly suggest that rational combination chemoimmunotherapies based on tumor immunoregulation may improve the efficacy of treatment

Interleukin 21 enhances antibody-mediated tumor rejection

Interleukin-21 (IL-21) is a cytokine with structural and sequence homology to IL-2 and IL-15 that has antitumor activity alone in mouse experimental tumor models and a tolerable safety profile in phase I trials in patients with metastatic melanoma and renal cell carcinoma. Several monoclonal antibodies (mAb) targeted at tumor-associated antigens also have improved antitumor activities in mice when used in combination with IL-21. Recently, we described a rational three antibody-based approach (triple mAb, TrimAb) to eradicating established mouse tumors that required the generation oftumor -reactive CD8 T cells and IFN-γ. Herein, we show that sequentially combining TrimAb with recombinant IL-21 can significantly improve the antitumor activity of this combination against very advanced disease. These data further support the use of IL-21 in adjuvant settings where strong T cell-mediated immune responses to tumors can be generated

Toll-like receptor triggering and T-cell costimulation induce potent antitumor immunity in mice

Purpose: To determine the antitumor activity of a novel combination of two immunomodulatory agents that simultaneously directmultiple components of immunity against cancer. Experimental Design: We combined the Toll-like receptor agonist CpG 1826 with a Tcell costimulatory antibody specific for CD137 in an optimal treatment route and dosing schedule against established tumors in two mouse models. Mechanistic insight was gained using gene-deficient mice and cell-depleting antibodies. Results: The combination was shown to eradicate tumors in a large proportion of mice. Crucial roles for CD8 T cells, natural killer cells, and IFNs were shown. CpG and anti-CD137 injection led to activation of dendritic cells and optimal expansion of activated T cells in the blood. Macrophages were not necessary for therapeutic effect, and indeed depletion of macrophages in vivo enhanced therapy leading to tumor rejection in 100% of mice, which has not been previously reported in the immunotherapeutic setting. Long-term surviving mice were resistant to tumor rechallenge, demonstrating immunologic memory. In addition, we show, for the first time, that mice lacking B cells have a total loss of a recall response against tumor, suggesting a role for B cells in the induction of antitumor immunologic memory. Conclusion: This study provides support for the use of a novel combination of immunomodulatory agents stimulating multiple facets of immunity for the effective immunotherapy of cancer

Combined natural killer T-cell-based immunotherapy eradicates established tumors in mice

A rational monoclonal antibody (mAb)-based antitumor therapy approach has previously been shown to eradicate various established experimental and carcinogen-induced tumors in a majority of mice. This therapy comprised an agonistic mAb reactive with tumor necrosis factor-related apoptosis-inducing ligand receptor (DR5), expressed by tumor cells, an agonistic anti-CD40 mAb to mature dendritic cells, and an agonistic anti-4-1BB mAb to costimulate CD8 T cells. Because agonists of CD40 have been toxic in patients, we were interested in substituting anti-CD40 mAb with other dendritic cell-maturing agents, such as glycolipid ligands recognized by invariant natural killer T (iNKT) cells. Here, we show that CD1d-restricted glycolipid ligands for iNKT cells effectively substitute for anti-CD40 mAb and reject established experimental mouse breast and renal tumors when used in combination with anti-DR5 and anti-4-1BB mAbs (termed "NKTMab" therapy). NKTMab therapy-induced tumor rejection was dependent on CD4 and CD8 T cells, NKT cells, and the cytokine IFN-γ. NKTMab therapy containing either α-galactosylceramide (α-GC) or α-C-galactosylceramide (α-c-GC) at high concentrations induced similar rates of tumor rejection in mice; however, toxicity was observed at the highest doses of α-GC (>250 ng/injection), limiting the use of this glycolipid. By contrast, even very low doses of α-c-GC (25 ng/injection) retained considerable antitumor activity when used in combination with anti-DR5/anti-4-1BB, and thus, α-c-GC showed a considerably greater therapeutic index. In summary, sequential tumor cell apoptosis and amplification of dendritic cell function by NKT cell agonists represents an exciting and novel approach for cancer treatment