Immunotherapy of lymphomas with T cells modified by anti-CD20 scFv/CD28/CD3zeta recombinant gene

Targeted human cytolytic fusion proteins at the cutting edge: harnessing the apoptosis-inducing properties of human enzymes for the selective elimination of tumor cells

Patient-specific targeted therapy represents the holy grail of anti-cancer therapeutics, allowing potent tumor depletion without detrimental off-target toxicities. Disease-specific monoclonal antibodies have been employed to bind to oncogenic cell-surface receptors, representing the earliest form of immunotherapy. Targeted drug delivery was first achieved by means of antibody-drug conjugates, which exploit the differential expression of tumor-associated antigens as a guiding mechanism for the specific delivery of chemically-conjugated chemotherapeutic agents to diseased target cells. Biotechnological advances have expanded the repertoire of immunology-based tumor-targeting strategies, also paving the way for the next intuitive step in targeted drug delivery: the construction of recombinant protein drugs consisting of an antibody-based targeting domain genetically fused with a cytotoxic peptide, known as an immunotoxin. However, the most potent protein toxins have typically been derived from bacterial or plant virulence factors and commonly feature both off-target toxicity and immunogenicity in human patients. Further refinement of immunotoxin technology thus led to the replacement of monoclonal antibodies with humanized antibody derivatives, including the substitution of non-human toxic peptides with human cytolytic proteins. Preclinically tested human cytolytic fusion proteins (hCFPs) have proven promising as non-immunogenic combinatory anti-cancer agents, however they still require further enhancement to achieve convincing candidacy as a single-mode therapeutic. To date, a portfolio of highly potent human toxins has been established; ranging from microtubule-associated protein tau (MAP tau), RNases, granzyme B (GrB) and death-associated protein kinase (DAPk). In this review, we discuss the most recent findings on the use of these apoptosis-inducing hCFPs for the treatment of various cancers.

Human Granzyme B Based Targeted Cytolytic Fusion Proteins

Cancer immunotherapy aims to selectively target and kill tumor cells whilst limiting the damage to healthy tissues. Controlled delivery of plant, bacterial and human toxins or enzymes has been shown to promote the induction of apoptosis in cancerous cells. The 4th generation of targeted effectors are being designed to be as humanized as possible—a solution to the problem of immunogenicity encountered with existing generations. Granzymes are serine proteases which naturally function in humans as integral cytolytic effectors during the programmed cell death of cancerous and pathogen-infected cells. Secreted predominantly by cytotoxic T lymphocytes and natural killer cells, granzymes function mechanistically by caspase-dependent or caspase-independent pathways. These natural characteristics make granzymes one of the most promising human enzymes for use in the development of fusion protein-based targeted therapeutic strategies for various cancers. In this review, we explore research involving the use of granzymes as cytolytic effectors fused to antibody fragments as selective binding domains.

Strategies to genetically engineer T cells for cancer immunotherapy

Immunotherapy is one of the most promising and innovative approaches to treat cancer, viral infections, and other immune-modulated diseases. Adoptive immunotherapy using gene-modified T cells is an exciting and rapidly evolving field. Exploiting knowledge of basic T cell biology and immune cell receptor function has fostered innovative approaches to modify immune cell function. Highly translatable clinical technologies have been developed to redirect T cell specificity by introducing designed receptors. The ability to engineer T cells to manifest desired phenotypes and functions is now a thrilling reality. In this review, we focus on outlining different varieties of genetically engineered T cells, their respective advantages and disadvantages as tools for immunotherapy, and their promise and drawbacks in the clinic.

Peripheral T-Cell Lymphoma with Aberrant Expression of CD19, CD20, and CD79a: Case Report and Literature Review

A case of lymphoma of T-cell derivation with aberrant expression of three B-cell lineage markers (CD19, CD20, and CD79a), which was diagnosed on a left axillary excision, is described. Immunohistochemical studies and flow cytometry analysis demonstrated neoplastic cells expressing CD3, CD19, CD20, and CD79a with absence of CD4, CD8, CD10, CD30, CD34, CD56, CD68, TDT, MPO, PAX-5, and surface immunoglobulin. Gene rearrangement studies performed on paraffin blocks demonstrated monoclonal T-cell receptor gamma chain rearrangement with no evidence of clonal heavy chain rearrangement. The neoplastic cells were negative for Epstein-Barr virus (EBV) or Human Herpes Virus 8 (HHV-8). At the time of diagnosis, the PET scan demonstrated hypermetabolic neoplastic cells involving the left axilla, bilateral internal jugular areas, mediastinum, right hilum, bilateral lungs, and spleen. However, bone marrow biopsy performed for hemolytic anemia revealed normocellular bone marrow with trilineage maturation. The patient had no evidence of immunodeficiency or infection with EBV or HHV-8. This is the first reported case of a mature T-cell lymphoma with aberrant expression of three B-cell lineage markers. The current report also highlights the need for molecular gene rearrangement studies to determine the precise lineage of ambiguous neoplastic clones.

Developing strategies in the immunotherapy of leukemias

BACKGROUND

In the current treatment paradigms for leukemias, hematopoietic stem cell transplant (HSCT) is considered the best option with a curative potential although more often than not it simply delays disease progression. Advances are needed, both in current therapies and in the development of new strategies. Partly from studying the nuances of the curative potential of stem cell transplant, we have come to appreciate the relevance of the immune response and the potential of immunotherapy.

METHODS

This review article summarizes the recent advances in the field of immunology and immunotherapy for leukemia.

RESULTS

In passive immunotherapy, recent progress in chimeric T-cell antigen receptor technology has been encouraging. In active immunotherapy, a cancer vaccine may potentially enhance HSCT. An overview of various clinical studies of peptide vaccination strategies focusing on molecular targets such as the Wilms' tumor gene 1 (WT1), proteinase 3 (PR3), and receptor for hyaluronan acid-mediated motility (RHAMM) is provided. Cell-based vaccination strategies are also briefly explored.

CONCLUSIONS

The immune system clearly has the capacity to recognize and react to leukemic cells, and recent evidence directs our attention to the importance of mounting inflammatory and CD4 T-cell responses to complement and support the cytotoxic activity elicited by peptide vaccines.

Gene therapy of malignant solid tumors by targeting erbB2 receptors and by activating T cells

One of the strategies to improve the outcome of anti-erbB2-mediated immunotherapy is to combine anti-erbB2 antibodies with T-cell-based adoptive immunotherapy, which can be achieved by expressing anti-erbB2 mAb on the surface of T cells. A single-chain variable fragment (scFv) from an anti-erbB2 mAb has been expressed on T cell surface to bind to erbB2-positive cells, and CD3ζ has been expressed as a fusion partner at C terminus of this scFv to transduce signals. T cells grafted with this chimeric scFv/CD3ζ were able to specifically attack target tumor cells with no MHC/Ag restriction. To test the effects of CD28 signal on cellular activation and antitumor effectiveness of chimeric scFv/CD3ζ-modified T cells, we constructed a recombinant anti-erbB2 scFv/Fc/CD28/CD3ζ gene in a retroviral vector. T cells expressing anti-erbB2 scFv/Fc/CD28/CD3ζ specifically lyzed erbB2-positive target tumor cells and secreted not only interferon-γ (IFN-γ) but also IL-2 after binding to their target cells. Our data indicate that CD3 and CD28 signaling can be delivered in one molecule, which is sufficient for complete T cell activation without exogenous B7/CD28 co-stimulation.

Inhibition of p38 MAPK activity in B-NHL Raji cells by treatment with engineered CD20-specific T cells

Adoptive immunotherapy with T cells expressing CD20-specific chimeric T-cell receptors is a promising approach to lymphoma therapy. However, modification of the cellular signaling pathways in target tumor cells by treatment with engineered CD20-specific T cells has yet to be fully elucidated. In this study, the non-Hodgkin's lymphoma Raji cell line was co-cultured with T cells that were genetically modified with anti-CD20scFvFc/CD28/CD3ζ or anti-CD20scFvFc gene. The cytolytic activity of engineered CD20-specific T cells and IL-10 secretion was quantitated by Cytotoxicity and ELISA assays, respectively. The engineered CD20-specific T cells and Raji cells were sorted using flow cytomety for the Western blot analysis. Treatment of Raji cells with T cells genetically modified with anti-CD20scFvFc/CD28/CD3ζ chimera (compared to anti-CD20scFvFc) yielded a higher cytotoxicity against Raji cells in vitro. Additionally, we found that engineered CD20-specific T cells caused a decrease in IL-10 secretion and inhibition of phosphor-STAT3 and Bcl-2 expression in Raji cells, possibly through the down-regulation of p38 MAPK and NF-κB activity. These results indicate that the treatment of Raji cells with engineered CD20-specific T cells inhibited the cellular p38 MAPK signaling pathways, which enhanced its antitumor activities against CD20-positive tumor cells.

Potential therapeutic strategy for non-Hodgkin lymphoma by anti-CD20scFvFc/CD28/CD3zeta gene tranfected T cells

Background

Anti-CD20 monoclonal antibody treatment has not only increased survival and cure rates in many non-Hodgkin lymphomas, but also has prompted an explosion in the development of novel antibodies and biologically active substances with specific cellular targets in the field of malignancies treatment. Since the robust immune responses are elicited by the gene-modified T cells, gene based T cell therapy may also provide a powerful tool for cancer immunotherapy.

Methods

In this study, we developed a vector construction encoding a chimeric T cell receptor that recognizes the CD20 antigen and delivers co-stimulatory signals to achieve T cell activation. One non-Hodgkin lymphoma cell line Raji cells co-cultured with peripheral blood-derived T cells were stably transfected with anti-CD20scFvFc/CD28/CD3zeta gene or anti-CD20scFvFc gene. T cells expressing anti-CD20scFvFc/CD28/CD3zeta or anti-CD20scFvFc gene co-cultured with CD20 positive Raji cells for different times. Cell lysis assay was carried by [³H]TdR release assay. The expressions of Fas, Bcl-2 and Caspase-3 of Raji cells were detected by flow cytometric. The secretion of IFN-gamma and IL-2 in co-culture medium was tested by ELISA assay. Activity of AP-1 was analyzed by EMSA.

Results

Following efficient transduction of peripheral blood-derived T cells with anti-CD20scFvFc/CD28/CD3zeta gene, an obvious cell lysis of Raji cells was observed in co-culture. T cells transduced anti-CD20scFvFc/CD28/CD3zeta gene had superior secretion of IFN-gamma and IL-2 compared to T cells transduced anti-CD20scFvFc gene. Also it led to a much stronger Fas-induced apoptosis signaling transduction in target cancer cells.

Conclusion

So adoptively T cells transduced anti-CD20scFvFc/CD28/CD3zeta gene mediates enhanced anti-tumor activities against CD20 positive tumor cells, suggesting a potential of gene-based immunotherapy for non-Hodgkin lymphoma.

Non-MHC-dependent redirected T cells against tumor cells

Adoptive transfer of T cells with restricted tumor specificity provides a promising approach to immunotherapy of cancers. However, the isolation of autologous cytotoxic T cells that recognize tumor-associated antigens is time consuming and fails in many instances. Alternatively, gene modification with tumor antigen-specific T-cell receptors (TCR) or chimeric antigen receptors (CARs) can be used to redirect the specificity of large numbers of immune cells toward the malignant cells. Chimeric antigen receptors are composed of the single-chain variable fragment (scFv) of a tumor-recognizing antibody cloned in frame with human T-cell signaling domains (e.g., CD3zeta, CD28, OX40, 4-1BB), thus combining the specificity of antibodies with the effector functions of cytotoxic T cells. Upon antigen binding, the intracellular signaling domains of the CAR initiate cellular activation mechanisms including cytokine secretion and cytolysis of the antigen-positive target cell.In this chapter, we provide detailed protocols for large-scale ex vivo expansion of T cells and manufacturing of medium-scale batches of CAR-expressing T cells for translational research by mRNA electroporation. An anti-CD19 chimeric receptor for the targeting of leukemias and lymphomas was used as a model system. We are currently scaling up the protocols to adapt them to cGMP production of a large number of redirected T cells for clinical applications.

Adoptive immunotherapy for cancer: the next generation of gene-engineered immune cells

Adoptive cellular immunotherapy involving transfer of tumor-reactive T cells has shown some notable antitumor responses in a minority of cancer patients. In particular, transfer of tumor-infiltrating lymphocytes has resulted in long-term objective responses in patients with advanced melanoma. However, the inability to isolate sufficient numbers of tumor-specific T cells from most malignancies has restricted the broad utility of this approach. An emerging approach to circumvent this limitation involves the genetic modification of effector cells with T cell receptor (TCR) transgenes or chimeric single-chain variable fragment (scFv) receptors that can specifically redirect T cells to tumor. There has been much progress in the design of TCR and scFv receptors to enhance the antigen-specific activation of effector cells and their trafficking and persistence in vivo. Considerable effort has been directed toward improving the safety of this approach and reducing the immunogenicity of the receptor. This review discusses the latest developments in the field of adoptive immunotherapy using genetically modified immune cells that have been transduced with either TCR or scFv receptor transgenes and used in preclinical and clinical settings as anticancer agents.

Primary cutaneous peripheral T-cell lymphoma with aberrant coexpression of CD20: case report and review of the literature

We report an unusual case of primary cutaneous T-cell lymphoma in a 45-year-old male showing expression of the B-cell marker CD20. The lesion presented as a large plaque on the right shin and rapidly developed into additional lesions on the right lower leg and right anterior chest. Despite therapy, bone involvement was discovered at 1 year after initial presentation. Punch biopsy of the right leg revealed a diffuse, atypical dermal lymphocytic infiltrate with papillary edema and no epidermotropism. The atypical cells strongly expressed the T-cell markers CD3, CD2, and CD43, with additional expression of cytotoxic T-cell markers CD8, cytotoxic granule-associated RNA binding protein (TIA-1), and granzyme B and loss of CD7 by immunohistochemistry (IHC). In addition, the atypical cells with the above phenotype exhibited moderate expression of CD20 by IHC. Coexpression of CD8 and CD20 in the atypical cells was confirmed by a dual-labeled IHC stain. Clonal rearrangements of the T-cell receptor gamma- and beta-chain genes were detected by polymerase chain reaction; however, there was no expression of T-cell receptor beta-chain identified by IHC. In conclusion, we present a case a of CD8-positive primary cutaneous T-cell lymphoma with CD20 expression, exhibiting aggressive behavior.

The promise and potential pitfalls of chimeric antigen receptors

One important purpose of T cell engineering is to generate tumor-targeted T cells through the genetic transfer of antigen-specific receptors, which consist of either physiological, MHC-restricted T cell receptors (TCRs) or non MHC-restricted chimeric antigen receptors (CARs). CARs combine antigen-specificity and T cell activating properties in a single fusion molecule. First generation CARs, which included as their signaling domain the cytoplasmic region of the CD3zeta or Fc receptor gamma chain, effectively redirected T cell cytotoxicity but failed to enable T cell proliferation and survival upon repeated antigen exposure. Receptors encompassing both CD28 and CD3zeta are the prototypes for second generation CARs, which are now rapidly expanding to a diverse array of receptors with different functional properties. First generation CARs have been tested in phase I clinical studies in patients with ovarian cancer, renal cancer, lymphoma, and neuroblastoma, where they have induced modest responses. Second generation CARs, which are just now entering the clinical arena in the B cell malignancies and other cancers, will provide a more significant test for this approach. If the immunogenicity of CARs can be averted, the versatility of their design and HLA-independent antigen recognition will make CARs tools of choice for T cell engineering for the development of targeted cancer immunotherapies.