Kotaro Miyao

A Tet-On Inducible System for Controlling CD19-Chimeric Antigen Receptor Expression upon Drug Administration

On-target/off-tumor effects can be problematic if the antigen target for CAR T-cell therapy is also expressed on normal tissue. An inducible CAR expression strategy was used that controlled CAR expression and shows promise in discriminating between tumor and B-cell expression of CD19. T cells genetically modified with a CD19 chimeric antigen receptor (CD19CAR) are remarkably effective against B-cell malignancies in clinical trials. However, major concerns remain regarding toxicities, such as hypogammaglobulinemia, due to B-cell aplasia or severe cytokine release syndrome after overactivation of CAR T cells. To resolve these adverse events, we aimed to develop an inducible CAR system by using a tetracycline regulation system that would be activated only in the presence of doxycycline (Dox). In this study, the second-generation CD19CAR was fused into the third-generation Tet-On vector (Tet-CD19CAR) and was retrovirally transduced into primary CD8+ T cells. Tet-CD19CAR T cells were successfully generated and had minimal background CD19CAR expression without Dox. Tet-CD19CAR T cells in the presence of Dox were equivalently cytotoxic against CD19+ cell lines and had equivalent cytokine production and proliferation upon CD19 stimulation, compared with conventional CD19CAR T cells. The Dox(+) Tet-CD19CAR T cells also had significant antitumor activity in a xenograft model. However, without Dox, Tet-CD19CAR T cells lost CAR expression and CAR T-cell functions in vitro and in vivo, clearly segregating the “On” and “Off” status of Tet-CD19CAR cells by Dox administration. In addition to suicide-gene technology, controlling the expression and the functions of CAR with an inducible vector is a potential solution for CAR T-cell therapy–related toxicities, and may improve the safety profile of CAR T-cell therapy. This strategy might also open the way to treat other malignancies in combination with other CAR or TCR gene–modified T cells. Cancer Immunol Res; 4(8); 658–68. ©2016 AACR. See related Spotlight by June, p. 643.

Programmed Death-Ligand 1 on Antigen-presenting Cells Facilitates the Induction of Antigen-specific Cytotoxic T Lymphocytes: Application to Adoptive T-Cell Immunotherapy.

Programmed death-ligand 1 (PD-L1) binds to programmed death-1 (PD-1) on activated T cells and contributes to T-cell exhaustion. PD-L1 expressed on antigen-presenting cells (APCs) could be thought to inhibit the induction of Ag-specific cytotoxic T lymphocytes (CTLs) by transducing negative signal into T cells; however, the roles of PD-L1 on APCs have not yet been well examined. Therefore, we evaluated the roles of PD-L1 on APCs in the induction of Ag-specific CTLs. CD3+ T cells isolated from cytomegalovirus (CMV)-seropositive healthy donors were stimulated with mature dendritic cells pulsed with CMV pp65-derived HLA-restricted peptides in the presence of anti-PD-L1 blocking antibody. Unexpectedly, PD-L1 blockade resulted in a less efficient induction of CMV-specific CTLs, suggesting that PD-L1 play a positive role in the induction of Ag-specific CTLs. For further evaluations and application to adoptive immunotherapy, we generated K562-based artificial APCs, which were retrovirally transduced with HLA class I molecules and various combinations of CD80/86 and PD-L1. K562/HLA+CD80/86+PD-L1 cells produced significantly higher induction of CMV-specific CTLs than K562/HLA or K562/HLA+CD80/86 cells without causing excessive differentiation or functional exhaustion of the induced CTLs, whereas PD-L1 itself did not have a stimulatory effect. Furthermore, only K562/HLA+CD80/86+PD-L1 cells pulsed with HLA-A*24:02-restricted Wilms tumor 1 (WT1) peptide clearly expanded WT1-specific CTLs from healthy donors. Our findings presumed that PD-L1 expressed on APCs along with CD80/86 enhanced the induction of Ag-specific CTLs probably depending on fine-tuning excessive stimulation of CD80/86, and that K562/HLA+CD80/86+PD-L1 cells has therapeutic potential as a novel type of artificial APCs for adoptive immunotherapy.

High incidence of extensive chronic graft-versus-host disease in patients with the REG3A rs7588571 non-GG genotype

Regenerating islet-derived protein 3 alpha (REG3A) is a biomarker of lower gastrointestinal graft-versus-host disease (GVHD); however, the biological role of REG3A in the pathophysiology of GVHD is not understood. Here, we examined the association between a single nucleotide polymorphism in the REG3A gene, rs7588571, which is located upstream and within 2 kb of the REG3A gene, and transplant outcomes including the incidence of GVHD. The study population consisted of 126 adult Japanese patients who had undergone bone marrow transplantation from a HLA-matched sibling. There was no association between rs7588571 polymorphism and the incidence of acute GVHD. However, a significantly higher incidence of extensive chronic GVHD was observed in patients with the rs7588571 non-GG genotype than in those with the GG genotype (Odds ratio 2.6; 95% confidence interval, 1.1–6.0; P = 0.029). Semi-quantitative reverse transcription PCR demonstrated that the rs7588571 non-GG genotype exhibited a significantly lower REG3A mRNA expression level than the GG genotype (P = 0.032), and Western blot analysis demonstrated that the rs7588571 non-GG genotype exhibited a trend toward lower REG3A protein expression level than the GG genotype (P = 0.053). Since REG proteins have several activities that function to control intestinal microbiota, and since intestinal dysbiosis is in part responsible for the development of GVHD, our findings lead to the novel concept that REG3A could have some protective effect in the pathogenesis of GVHD through the regulation of gut microbiota.

Impact of T-cell chimerism on relapse after cord blood transplantation for hematological malignancies: Nagoya Blood and Marrow Transplantation Group study

Impact of T-cell chimerism on relapse after cord blood transplantation for hematological malignancies: Nagoya Blood and Marrow Transplantation Group study

Testicular invading refractory multiple myeloma during bortezomib treatment successfully treated with lenalidomide: a case report.

Dear Editor, A 64-year-old man was diagnosed with symptomatic multiple myeloma (MM) in June 2009. No extramedullary region including the testes was detected. Serum protein electrophoresis showed IgA-κmonoclonal protein. Durie-Salmon stagewas IIIA and International Staging System stage was II. Treatment was initiated with pulsed dexamethasone and bortezomib (1.3 mg/m) twice weekly with dexamethasone (20 mg on the day of bortezomib administration and the next day).Without any adverse events, he achieved very good partial response (VGPR) after three cycles of bortezomib therapy [1]. Subsequently, he received high-dose melphalan (200 mg/m) followed by autologous stem cell transplantation (ASCT) in November 2009. After ASCT, he was followed up without any therapeutic agents. However, in September 2010, he complained of hip pain, and serum IgA level was elevated to 2,014 mg/dl. As recurrence of MM was diagnosed, we started weekly bortezomib with dexamethasone. The patient soon experienced improvement of symptoms, and serum IgA decreased to normal levels. In July 2011, during weekly bortezomib and dexamethasone, the patient noticed enlargement of his scrotum. Magnetic resonance image revealed enlarged bilateral testes. Serum IgA levels and all other laboratory data were normal. Bilateral orchidectomy was performed in October 2011. Microscopic examination showed positive results for CD56, CD138, and IgA and κ light chain (Fig. 1a, b). The pathological diagnosis wasmetastasis of plasma cell myeloma to the bilateral testes, and the right spermatic cord had positive margins. In November 2011, serum IgA was elevated to 2,304 mg/dl. At relapse of systemicMM including spermatic margins after orchidectomy, a 28-day cycle of lenalidomide (25 mg on days 1–21) and dexamethasone (40 mg on days 1, 8, 15, and 22) was initiated [2]. Serum IgA levels decreased to 1,026 mg/dl and reached a plateau without stump recurrence of the spermatic cord. After 6 cycles of lenalidomide, the patient was treated with cyclophosphamide, vincristine, adriamycin, and dexamethasone (C-VAD) and achieved VGPR after two cycles of C-VAD therapy. In August 2012, he successfully underwent a second ASCT. Two months after ASCT, he started a 28-day cycle of lenalidomide maintenance therapy (10mg on days 1–21) [3]. As of the time of writing, the patient remains alive without recurrence.

Identification of the novel deletion-type PML-RARA mutation associated with the retinoic acid resistance in acute promyelocytic leukemia

All-trans retinoic acid (ATRA) and arsenic trioxide (ATO) are essential for acute promyelocytic leukemia (APL) treatment. It has been reported that mutations in PML-RARA confer resistance to ATRA and ATO, and are associated with poor prognosis. Although most PML-RARA mutations were point mutations, we identified a novel seven amino acid deletion mutation (p.K227_T233del) in the RARA region of PML-RARA in a refractory APL patient. Here, we analyzed the evolution of the mutated clone and demonstrated the resistance of the mutated clone to retinoic acid (RA). Mutation analysis of PML-RARA was performed using samples from a chemotherapy- and ATRA-resistant APL patient, and the frequencies of mutated PML-RARA transcript were analyzed by targeted deep sequencing. To clarify the biological significance of the identified PML-RARA mutations, we analyzed the ATRA-induced differentiation and PML nuclear body formation in mutant PML-RARA-transduced HL-60 cells. At molecular relapse, the p.K227_T233del deletion and the p.R217S point-mutation in the RARA region of PML-RARA were identified, and their frequencies increased after re-induction therapy with another type of retinoiec acid (RA), tamibarotene. In deletion PML-RARA-transduced cells, the CD11b expression levels and NBT reducing ability were significantly decreased compared with control cells and the formation of PML nuclear bodies was rarely observed after RA treatment. These results indicate that this deletion mutation was closely associated with the disease progression during RA treatment.

Introduction of Genetically-Modified CD3ζ Improves Proliferation and Persistence of Antigen-specific CTLs

It may be safer to improve adoptive T-cell therapy through increased signaling rather than increased antigen affinity of the TCRs. Modifying intracellular signaling enhanced the proliferation and persistence of CTLs while improving antitumor efficacy. The clinical efficacy of T-cell therapies based on T cells transduced with genes encoding tumor-specific T-cell receptors (TCR-T) is related to the in vivo persistence of the T cells. To improve persistence without modifying TCR affinity, we instead modified intracellular signaling, using artificial T cell–activating adapter molecules (ATAM), generated by inserting the intracellular domain (ICD) of activating T-cell signaling moieties into CD3ζ. ATAMs with the ICD of either CD28 or 4-1BB were generated, assembled into the TCR complex as a part of CD3ζ, and enhanced downstream signaling from the supramolecular activation cluster. ATAMs were retrovirally introduced into human CMV-specific or NY-ESO-1–specific TCR-transduced CD8+ T lymphocytes, and downstream functionality was then examined. ATAM-transduced NY-ESO-1 TCR-T cells were also investigated using the U266-xenograft mouse model. ATAMs were successfully transduced and localized to the cell membrane. ATAM-transduced CMV-specific T cells retained their cytotoxic activity and cytokine production against peptide-pulsed target cells without altering antigen-specificity and showed resistance to activation-induced cell death. Upon both single and repeated stimulation, CD3ζ/4-1BB–transduced T cells had superior proliferation to the CD3ζ-transduced T cells in both the CMV-specific and the NY-ESO-1 TCR-T models and significantly improved antitumor activity compared with untransduced T cells both in vitro and in a mouse xenograft model. ATAM-transduced TCR-T cells demonstrated improved proliferation and persistence in vitro and in vivo. This strategy to control the intracellular signaling of TCR-T cells by ATAM transduction in combination with various tumor-specific TCRs may improve the efficacy of TCR-T therapy. Cancer Immunol Res; 6(6); 733–44. ©2018 AACR.

Quantitative assessment of T cell clonotypes in human acute graft-versus-host disease tissues

Owing to the difficulty in isolating T cells from human biopsy samples, the characteristics of T cells that are infiltratinghuman acute graft-versus-host disease (GVHD) tissues remain largely uninvestigated. In the present study, TCR-β deep sequencing of various GVHD tissue samples and concurrent peripheral blood obtained from transplant recipients was performed in combination with functional assays of tissue-infiltrating T cell clones. The T cell repertoire was more skewed in GVHD tissues than in the peripheral blood. The frequent clonotypes differed from tissue to tissue in the same patient, and the frequent clonotypes in the same tissue differed from patient to patient. Two T cell clones were successfully isolated from GVHD skin of a patient. In a cytotoxicity assay, both Tcell clones lysed patient peripheral blood mononuclear cells, but not donor-derived Epstein-Barr virus-transformed lymphoblastoid cells. Their clonotypes were identical to the most and second most frequent T cell clonotypes in the original GVHD skin and accounted for almost all of the skin-infiltrating T cells. These results suggest that human acute GVHD may result from only a few different alloreactive cytotoxic T cell clones, which differ from tissue to tissue and from patient to patient. The characterization of T cells infiltrating human GVHD tissues should be further investigated.

Influence of melphalan plus fludarabine-conditioning regimen in elderly patients aged ⩾ 55 years with hematological malignancies

Influence of melphalan plus fludarabine-conditioning regimen in elderly patients aged ⩾ 55 years with hematological malignancies

O2-4-5BORTEZOMIB COMBINED CHEMOTHERAPY FOR MULTIPLE MYELOMA PATIENTS WHO ARE CANDIDATE FOR AUTOLOGOUS STEM CELL TRANSPLANT

Abstract Background: Novel agents for multiple myeloma (MM) have been reported to increase complete remission (CR) rates compared with conventional chemotherapy. It is also estimated that deeper remission may improve survival in MM patients. We retrospectively evaluated the efficacy of novel agents combined induction chemotherapy to treat MM patients who are candidate for autologous stem cell transplant (ASCT). Patients and methods: Thirty seven newly diagnosed MM patients who underwent ASCT at our hospital from April 2004 to September 2012 were retrospectively analyzed. The 20 patients who underwent ASCT before July 2009 were treated with conventional induction Chemotherapy: doxorubicin, vincristine, dexamethasone (VAD) or cyclophosphamide plus VAD (C-VAD), and the recent 17 patients were treated with bortezomib and dexamethasone (BD) followed by ASCT. Results: The median age of patients were 61yr (range: 46-70). The median follow up time was 1041 days (range: 25-2804). There were no significant differences in the patient characteristics between those two groups other than the year of transplant. CR rate was significantly higher in BD group compared with conventional treatment group (56.3% vs. 15.0%, p Conclusion: Bortezomib combined induction chemotherapy for MM may improve survival by achieving deeper remission in ASCT setting.