The novel immunotherapeutic molecule T11TS modulates glioma-induced changes of key components of the immunological synapse in favor of T cell activation and glioma abrogation

Therapeutic intervention of glioma with the novel antineoplastic agent T11TS: the story so far

The disease relevance of novel therapeutic agent T11TS, established first by the authors' group, was shown to ameliorate experimental glioma through multimodal mechanistic activities. T11TS reverses immunosuppression in glioma, causing profound effects on immune potentiation via peripheral, intracranial and hematopoietic cells. T-cell signaling in glioma is reversed by T11TS, modulating cytokine levels and favoring apoptotic killing of glioma cells. T11TS arrests the glioma cell cycle at the G1 phase via activation of p21. VEGF downregulation hypophosphorylates the Akt pathway. T11TS hinders endothelial cell progression and metastasis by arresting matrix degradation, inhibiting the Ras-Raf and Akt-PTEN pathways and initiating inflammatory changes, causing apoptosis. T11TS is effective against in vitro human glioma. Toxicity studies demonstrate that T11TS is nontoxic. The authors' study promise translational research with T11TS.

Regulation of key molecules of immunological synapse by T11TS immunotherapy abrogates Cryptococcus neoformans infection in rats

Cryptococcus neoformans infects and disseminates in hosts with diminished T cell responses. The immunomodulator T11TS (T11 target structure) had profound potential in glioma as well as C. neoformans infected model for disease amelioration. It is been established by our group that T11TS potentiates Calcineurin-NFAT pathway in T cells of C. neoformans infected rats. We investigated the upstream Immunological Synapse (IS) molecules that are vital for the foundation of initial signals for downstream signaling, differentiation and proliferation in T cells. Improved RANTES level in the T11TS treated groups suggests potential recruitment of T cells. Down-regulation of TCRαβ, CD3ζ, CD2, CD45 and CD28 molecules by cryptococcus were boosted after T11TS therapy. Heightened expression of inhibitory molecule CTLA-4 in cryptococcosis was dampened by T11TS. The decline of MHC I, MHC II and CD80 expression on macrophages by C. neoformans were enhanced by T11TS. The dampening of positive regulators and upsurge of negative regulators of the IS during cryptococcosis was reversed with T11TS therapy resulting in enhanced clearance of fungus from the lungs as envisaged by our histological studies. This preclinical study with T11TS opens a new prospect for potential immunotherapeutic intervention against the devastating C. neoformans infection with positive aspect for the long-term solution and a safer immunotherapeutic regimen.

T11TS immunotherapy potentiates the repressed calcineurin-NFAT signalling pathway of T cells in Cryptococcus neoformans infected rats: a cue towards T-cell activation for antifungal immunity

AIMS

To examine the modulation of the interacting partners of the calcineurin (CaN)-NFAT pathway in T cells during Cryptococcus neoformans fungal infection and post-T11TS immunotherapy.

METHODS AND RESULTS

Wistar rats were infected with C. neoformans and followed by immunotherapy with immune-potentiator T11TS. T cells were analysed by flow cytometry, immunoblotting and nuclear translocation study. The signalling proteins LCK, FYN, LAT, PLCγ1 and CaN in T cells were regulated by C. neoformans infection resulting in reduced nuclear translocation of NFAT and IL-2 expression. Following T11TS immunotherapy, the expressions of the above-mentioned proteins were boosted and thus resulting in the clearance of C. neoformans from lung and spleen.

CONCLUSIONS

The precise mechanism of suppression of the T-cell function by C. neoformans is still unknown. Previously, we have shown that T11TS positively regulates the function of T cells to abrogate glioma and other immunosuppressive conditions. T11TS immunotherapy increased the expression of the above signalling partners of the CaN-NFAT pathway in T cells and improved nuclear retention of NFAT. As a result, an increased IL-2 expression leads to activation and proliferation of T cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results demonstrate the role of T11TS in restoring the CaN-NFAT signalling pathway in T cells. It identifies T11TS as an immunotherapeutic agent with potential clinical outcomes to counteract C. neoformans infection.

T11TS immunotherapy augments microglial and lymphocyte protective immune responses against Cryptococcus neoformans in the brain

Cryptococcus neoformans, the encapsulated yeast acquired through inhalation, remains localized in lungs, but harbours the CNS in immunocompromised individuals. Several treatment regimes have failed combating this disease totally, but long-term usage of drugs leads to organ damage. As T11-target structure (T11TS) has documented profound immune potentiation, we aimed to investigate the role of microglia, pivotal immune cells of brain in ameliorating cryptococcosis, with T11TS immunotherapy. Murine model with C neoformans infection was prepared by intraperitoneal injection and the brains of rats examined 7 days post-infections for histopathology by PAS and Alcian blue staining corroborated with organ fungal burden evidencing restorative T11TS action on Cryptococcal meningitis. Immunotherapy with three doses of T11TS, a CD2 ligand, in C neoformans infected rats, upregulates toll-like receptors 2, -4 and -9 of microglia, indicating increased phagocytosis of the fungus. Flowcytometric analysis revealed increased numbers of T11TS treated brain infiltrating CD4⁺ and CD8⁺ T-lymphocytes along with increased MHC I and MHC II on microglia, activating the infiltrating lymphocytes aiding the killing mechanism. Present study also indicated that T11TS increased production of Th1 inflammatory cytokines conducive to fungal elimination while the inhibitory Th2 cytokines were dampened. This preclinical study is first of its kind to show that T11TS effected profound immune stimulation of microglial activity of C neoformans infected rats eradicating residual fungal burden from the brain and can be a useful therapeutic strategy in fighting against this deadly disease.

Unravelling the apoptotic mechanisms in T-lymphocytes in an animal model for pollen induced airway allergy and studying the impact of specific immunotherapy

Asthma is a chronic inflammatory disorder of the airways, increasing in prevalence worldwide. Reduced T cell apoptosis may interfere with the down-regulation of an immune response resulting in T cell accumulation contributing to the chronic inflammation of asthma. Most studies focused so far on apoptosis of eosinophils but the detailed role of T lymphocytes apoptosis in allergic diseases is unclear yet. The present experimental study was designed to discern the modulation of various apoptotic proteins of splenic T lymphocytes in a previously established rat model of Alstonia scholaris pollen induced airway allergy. Flowcytometry, immunoblotting, and immunofluorescence imaging techniques were employed for the present investigation. Annexin-V studies registered early apoptotic rate of lymphocytes with allergen sensitization and challenge which was corrected following mucosal immunotherapy. The study demonstrates that allergen sensitization and challenge reduced apoptosis of splenic T-lymphocytes via Fas mediated extrinsic pathway, Bax/Bcl2 regulated intrinsic pathway and also perforin/granzyme mediated pathway which were normalized following allergen specific intranasal immunotherapy. Inadequate T cell apoptosis in asthma appears to interfere with normal T cell elimination, resulting in T cell accumulation, which contributes to chronic inflammation and may be the major underlying cause for tissue damage which can be modulated by intranasal immunotherapy. Thus the apoptosis inducing effect of allergen immunotherapy necessitates more studies to elaborate on its effects on various effector cells of airway inflammation.

T11TS immunotherapy repairs PI3K-AKT signaling in T-cells: Clues toward enhanced T-cell survival in rat glioma model

Malignant glioma is the most fatal of astrocytic lineage tumors despite therapeutic advances. Onset and progression of gliomas is accompanied by severe debilitation of T-cell defense and T-cell survival. One of the chief contributors to T-cell survival downstream of activation is the PI3K-AKT pathway. Our prior studies showed that the novel immunotherapeutic molecule T11-target structure (T11TS) blocks T-cell apoptosis in glioma. We also showed activation of immunological synapse components and calcineurin-NFAT pathway following T11TS immunotherapy of glioma-bearing rats. This lead to investigations whether such T-cell activation upon T11TS therapy translates into activation of downstream PI3K/AKT signals which may be related to observed blockade of T-cell apoptosis. For the purpose, we assessed by flowcytometry and immunoblotting, expressions of PI3K, PDK1, AKT, p-AKT, and PTEN in splenic T-cells of normal, experimentally-induced glioma-bearing rats and glioma-bearing rats receiving first, second and third doses of T11TS. We also determined comparative nuclear translocation of NF-κB across groups. We found significant increases in T-cell expressions of PDK1, PI3K, and p-AKT in T11TS-treated animal groups compared to sharp downregulations in glioma. AKT levels remained unchanged across groups. PTEN levels declined sharply after T11TS immunotherapy. T11TS also caused enhanced NF-κB translocation to the T-cell nucleus compared to glioma group. Results showed heightened activation of the PI3K-AKT pathway in glioma-bearing rats following T11TS immunotherapy. These results illustrate the novel role of T11TS immunotherapy in ameliorating the PI3K pathway in T-cells in glioma-bearing animals to enhance T-cell survival, according greater defense against glioma. The study thus has far-reaching clinical outcomes.

Modulation of regulatory T cells by intranasal allergen immunotherapy in an experimental rat model of airway allergy

Allergic airway diseases such as asthma and allergic rhinitis are increasing in prevalence worldwide. The theory of an altered Th1/Th2 balance in allergic diathesis has recently been termed a "procrustean paradigm" as it failed to explain many preclinical findings. Regulatory T cells (Treg) have now been shown to be critical in T-cell homeostasis and in the maintenance of peripheral tolerance to allergens. Allergen specific immunotherapy (SIT) has been shown to induce regulatory T cells in allergic patients. Among various types of SIT, intranasal immunotherapy had not been studied in detail for the treatment of allergic airway diseases. So, there was a need to study the contribution of regulatory T cells and their mechanistic pathways following intranasal immunotherapy in-vivo. It had been previously shown that intranasal allergen immunotherapy using Alstonia scholaris pollen extract abrogates allergic airway inflammation with decline in IgE and Th2 cytokine levels. The present study for the first time offers a multi-targeted approach towards attenuation of airway allergy by the generation of CD4+CD25+Foxp3+T cells and other subsets of Treg cells like Tr1 cells, Th3 cells, CTLA4+Treg cells, and also modulation of various Treg cell surface molecules like GITR, OX40, CD39 and CD73 by intranasal immunotherapy in the same animal model. This animal experiment will thus help to chart out newer molecular targets for treating allergic asthma or rhinitis.

T11TS repress gliomagenic apoptosis of bone marrow hematopoietic stem cells

Combating gliomagenic global immunosuppression is one of the emerging key for improving prognosis in malignant glioma. Apoptosis plays a pivotal role within the adult hematopoietic system particularly in regulating the cells of immune system. Gliomagenic regulation of apoptotic mediators within bone marrow milieu has not been elucidated. We previously demonstrated that administration of membrane glycopeptides T11 target structure (T11TS) not only rejuvenate bone marrow hematopoietic stem cells (BMHSCs) from glioma mediated hibernation by inhibiting gliomagenic overexpression of Ang-1/Tie-2 but also stimulate glioma mediated diminution of expression CD34, c-kit, and Sca-1 markers. In the present study, we investigated the impact of glioma on apoptotic signaling cascades of BMHSCs and consequences following T11TS therapy. Bone marrow smear and Annexin V staining confirm gliomagenic acceleration of apoptotic fate of BMHSCs whereas T11TS treatment in glioma-bearing rats disrupted apoptosis of BMHSCs. Flowcytometry, immunoblotting, and immunofluorescence imagining results revealed multi potent T11TS not only significantly downregulates gliomagenic overexpression of Fas, Fas L, Bid, and caspase-8, the pro-apoptotic extrinsic mediators but also strongly inhibits cytosolic release of cytochrome-c, Apf-1, and Bax to deactivate gliomagenic caspase-9, 3 the key intrinsic apoptotic mediators followed by up modulation of anti-apoptotic Bcl-2 in glioma associated HSCs. T11TS is also able to diminish the perforin-granzyme B mediated apoptotic verdict of BMHSCs during gliomagenesis. The anti-apoptotic action of T11TS on glioma associated BMHSCs provide a crucial insight into how T11TS exerts its immunomodulatory action against glioma mediated immune devastation.

IL-13 receptor α2 stimulates human glioma cell growth and metastasis through the Src/PI3K/Akt/mTOR signaling pathway

Glioma is a malignant tumor that affects all kinds of people all over the world. It demonstrates remarkable infiltrative and invasive features. The high expression of interleukin-13 receptor subunit alpha-2 (IL-13Rα2) reportedly plays a pivotal role in some cancers. However, whether IL-13Rα2 contributes to glioma remains unknown. This study demonstrates that IL-13Rα2 is significantly up-regulated in human glioma tissue samples. It is also associated with late stages of disease progression and diminished survival in glioma patients. Gain- and loss-of-function studies demonstrate that IL-13Rα2 promotes the growth, migration, and invasion of glioma cells. In addition, mechanistic investigations show that IL-13Rα2 activates Scr, phosphatidylinositol 3 kinase (PI3K), Akt, and mTOR. Also, restraining Scr in glioma cells attenuates the activation of Scr/PI3K/Akt/mTOR pathway by IL-13Rα2, whereas the silencing of Scr markedly rescues the pro-invasive effect of IL-13Rα2. In conclusion, our results suggest that the high expression of IL-13Rα2 is significantly associated with the growth and metastasis of human glioma cells via the Scr/PI3K/Akt/mTOR pathway, while IL-13Rα2 may be a potential therapeutic target for glioma treatment.

Tristetraprolin exerts tumor suppressive functions on the tumorigenesis of glioma by targeting IL-13

The RNA-binding protein tristetraprolin (TTP) is an adenine/uridine (AU)-rich elements (AREs)-binding protein that can induce the decay of AREs containing mRNAs. In this study, we demonstrated that TTP is significantly down-regulated in human glioma tissue samples and cell lines. It is also associated with diminished survival in glioma patients. Gain- and loss-of-function studies demonstrated that TTP inhibited the growth, migration and invasion of glioma cells through regulation of interleukin (IL)-13. Furthermore, mechanistic investigations showed that TTP attenuated activation of PI3K/Akt/mTOR pathway by IL-13, and the ectopic expression of IL-13 markedly abrogated the anti-invasive effect of TTP. Additionally, TTP were found inversely correlated with IL-13 in glioma specimens. In conclusion, our results suggested that the low expression of TTP is significantly associated with the growth and metastasis of human glioma cells by targeting IL-13, while TTP may be a potential therapeutic target for glioma treatment.

Specific allergen immunotherapy attenuates allergic airway inflammation in a rat model of Alstonia scholaris pollen induced airway allergy

Pollen grains are well established to be an important cause of respiratory allergy. Current pharmacologic therapies for allergic asthma do not cure the disease. Allergen specific immunotherapy is the only treatment method which re-directs the immune system away from allergic response leading to a long lasting effect. The mechanism by which immunotherapy achieves this goal is an area of active research world-wide. The present experimental study was designed to develop an experimental model of allergic lung inflammation based on a relevant human allergen, Alstonia scholaris pollen, and to establish the immunological and cellular features of specific allergen immunotherapy using this same pollen extract. Our results revealed that Alstonia scholaris pollen sensitization and challenge causes eosinophilic airway inflammation with mucin hypersecretion. This is associated with increased total IgE, increased expression of FcɛRI on lung mast cells and increased levels of IL-4, IL-5 & IL-13 as confirmed by ELISA, in-situ immunofluorescence and FACS assay. Allergen specific immunotherapy reduced airway inflammation and also decreased total IgE level, FcɛRI expression, IL-4, IL-5 & IL-13 levels. It was further noted that the reduction of these levels was more by intra-nasal route than by intra-peritoneal route. Thus we present a novel animal model of Alstonia scholaris pollen allergic disease and specific allergen immunotherapy which will pave the way towards the development of better treatment modalities.

Disease relevance of T11TS-induced T-cell signal transduction through the CD2-mediated calcineurin-NFAT pathway: Perspectives in glioma immunotherapy

Malignant glioma is the most lethal of a wide array of CNS neoplasms. Its onset and progression are markedly associated with profound immunosupression and paralysis of T-cell survival and proliferation. Myriad immunotherapeutic strategies are presently used to target such T-cell anomalies in glioma. Our recent work has highlighted use of the novel glycopeptide, the CD2 ligand, T11 target structure (T11TS) as an immunotherapeutic agent against experimentally induced glioma in rats. We have shown that T11TS causes multi-target modulation of key components of the T-cell - antigen presenting cell (APC) immunological synapse. This consequently triggers T-cell activation so as to reverse glioma-induced changes to physiological levels. T11TS administration also causes CD2 upregulation. Earlier we also found T11TS to cause enhanced proliferation of both CD4+ and CD8+ T-cells in glioma conditions. These findings led us to believe that downstream CD2-stimulated "alternative pathway" of calcineurin-NFAT could be a possible target for modulation by T11TS. In the present paper we thus show that immunotherapy with T11TS induces a multi-targeted approach towards activation of this "alternative pathway" of T-cell signaling providing an immunotherapeutic advantage against glioma. We show here that T11TS immunotherapy causes positive modulations of the CD2 pathway-associated proteins, viz., p59fyn, protein kinase C-θ (PKC-θ), calcineurin and nuclear factor for activation of T-cells (NFAT) and hint that this may accord greater survival and proliferation advantage to T-cells of the glioma-bearing animals for augmented defence against glioma. These findings help open a molecular immunotherapeutic door - one which is directed towards clinical studies for glioma-immunotherapy using T11TS.