Mini-TCRs: Truncated T cell receptors to generate T cells from induced pluripotent stem cells

Allogeneic T cell platforms utilizing induced pluripotent stem cell (iPSC) technology exhibit significant promise for the facilitation of adoptive immunotherapies. While mature T cell receptor (TCR) signaling plays a crucial role in generating T cells from iPSCs, the introduction of exogenous mature TCR genes carries a potential risk of causing graft-versus-host disease (GvHD). In this study, we present the development of truncated TCRα and TCRβ chains, termed mini-TCRs, which lack variable domains responsible for recognizing human leukocyte antigen (HLA)-peptide complexes. We successfully induced cytotoxic T lymphocytes (CTLs) from iPSCs by employing mini-TCRs. Combinations of TCRα and TCRβ fragments were screened from mini-TCR libraries based on the surface localization of CD3 proteins and their ability to transduce T cell signaling. Consequently, mini-TCR-expressing iPSCs underwent physiological T cell development, progressing from the CD4 and CD8 double-positive stage to the CD8 single-positive stage. The resulting iPSC-derived CTLs exhibited comparable cytokine production and cytotoxicity in comparison to that of full-length TCR-expressing T lymphocytes when chimeric antigen receptors (CARs) were expressed. These findings demonstrate the potential of mini-TCR-carrying iPSCs as a versatile platform for CAR T cell therapy, offering a promising avenue for advancing adoptive immunotherapies.

Optimization of the proliferation and persistency of CAR T cells derived from human induced pluripotent stem cells

The effectiveness of chimaeric antigen receptor (CAR) T-cell immunotherapies against solid tumours relies on the accumulation, proliferation and persistency of T cells at the tumour site. Here we show that the proliferation of CD8αβ cytotoxic CAR T cells in solid tumours can be enhanced by deriving and expanding them from a single human induced-pluripotent-stem-cell clone bearing a CAR selected for efficient differentiation. We also show that the proliferation and persistency of the effector cells in the tumours can be further enhanced by genetically knocking out diacylglycerol kinase, which inhibits antigen-receptor signalling, and by transducing the cells with genes encoding for membrane-bound interleukin-15 (IL-15) and its receptor subunit IL-15Rα. In multiple tumour-bearing animal models, the engineered hiPSC-derived CAR T cells led to therapeutic outcomes similar to those of primary CD8 T cells bearing the same CAR. The optimization of effector CAR T cells derived from pluripotent stem cells may aid the development of long-lasting antigen-specific T-cell immunotherapies for the treatment of solid tumours.

The therapeutic potential of multiclonal tumoricidal T cells derived from tumor infiltrating lymphocyte-1derived iPS cells

Tumor-infiltrating lymphocytes (TIL), which include tumor-specific T lymphocytes with frequency, are used for adoptive cell transfer therapy (ACT) in clinical practice. The optimization of TIL preparation has been investigated to reduce the senescence and increase the abundance of TIL, as both the quality and quantity of the transferred cells have great influence on the outcome of TIL-based ACT (TIL-ACT). Considering the effects of cell reprogramming on senescence, we expected that the anti-tumor effect could be enhanced by TIL regeneration. To confirm this hypothesis, we established tumor-specific TIL-derived iPS cells (TIL-iPSC) with human colorectal cancer specimens. T cells differentiated from TIL-iPSC (TIL-iPS-T) retained not only intrinsic T cell functions and tumor specificity, but also exhibited improved proliferation capacity and additional killing activity. Moreover, less differentiated profiles and prolonged persistency were seen in TIL-iPS-T compared with primary cells. Our findings imply that iPSC technology has great potential for TIL-ACT.

Capturing human trophoblast development with naive pluripotent stem cells in vitro

Trophoblasts are extraembryonic cells that are essential for maintaining pregnancy. Human trophoblasts arise from the morula as trophectoderm (TE), which, after implantation, differentiates into cytotrophoblasts (CTs), syncytiotrophoblasts (STs), and extravillous trophoblasts (EVTs), composing the placenta. Here we show that naïve, but not primed, human pluripotent stem cells (PSCs) recapitulate trophoblast development. Naive PSC-derived TE and CTs (nCTs) recreated human and monkey TE-to-CT transition. nCTs self-renewed as CT stem cells and had the characteristics of proliferating villous CTs and CTs in the cell column of the first trimester. Notably, although primed PSCs differentiated into trophoblast-like cells (BMP4, A83-01, and PD173074 [BAP]-treated primed PSCs [pBAPs]), pBAPs were distinct from nCTs and human placenta-derived CT stem cells, exhibiting properties consistent with the amnion. Our findings establish an authentic paradigm for human trophoblast development, demonstrating the invaluable properties of naive human PSCs. Our system provides a platform to study the molecular mechanisms underlying trophoblast development and related diseases.

Abstract 1432: Enhanced effector responses of regenerated CAR-T cells derived from genome edited iPSCs

Chimeric antigen receptor (CAR) is an artificial protein that provides HLA-independent antigen specificity to T cells. CAR-T therapy has shown remarkable clinical responses especially in hematologic malignancies. But this therapy requires cell preparation for each patient and it cause some limitations for applicability of CAR-T therapy. We have reported regeneration of T cells from iPSCs (Cell Stem Cell. 2013). Since this technology can provide unlimited number of T cells, CAR-T therapy using iPSCs is thought to broaden its applicability. To target solid tumors, it is important to avoid immunosuppressive factors from tumor microenvironment and to exert sufficient cytotoxicity. Tumor reactive T cells are known to fall into anergy state by continuous antigen stimulations. To overcome immunosuppression in tumor microenvironment, enhancement of TCR signaling by modification of genes related to TCR signal is a promising strategy. Recent studies revealed that the efficacy of CAR-iPS-T cells are not equivalent to primary CAR-T cells. To enhance the efficacy of CAR-iPS-T cells and to produce resistant CAR-T cells to immunosuppression, we focused on TCR signaling pathway. We found that antigen reactivity of CAR-iPS-T cells was insufficient compared with primary CAR-T cells. To overcome the weakness of TCR signal, we disrupted genes negatively related to TCR signal and successfully enhanced TCR signal. As a result, genome edited CAR-iPS-T cells could persist longer in vivo and displayed enhanced tumor suppressive function comparable with primary CAR-T cells. Genome edited iPSCs can be a unlimited cell source of enhanced CAR-T cells. These findings indicate that regenerated CAR-T cells derived from genome edited iPSCs would be a promising CAR-T therapy which would overcome immunosuppressive tumor microenvironment.

Citation Format: Tatsuki Ueda, Shoichi Iriguchi, Yohei Kawai, Atsutaka Minagawa, Hiroyuki Miyoshi, Seitaro Terakura, Yasushi Uemura, Knut Woltjen, Yuzo Kodama, Hiroshi Seno, Yasumichi Hitoshi, Tetsuya Nakatsura, Koji Tamada, Shin Kaneko. Enhanced effector responses of regenerated CAR-T cells derived from genome edited iPSCs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1432.

Assessment of "look-alike" packaging designs related to medication errors using information technology

This study aimed to assess the similarity among press-through pack (PTP) sheets of pharmaceutical products in Japan. The appearance of PTPs was assessed using a pharmaceutical design database (PDD) of 2,750 pharmaceutical tablets comprising approximately 40 % of the 6,840 products marketed in Japan. Package sheet color (Sc), tablet color (Tc), character color (Cc), sheet line color (SLc), and upper color (Uc) were used to evaluate the uniformity of PTP sheet design. To assess the risk of misidentification, 1,000 prescriptions for 82,273 cancer patients were retrieved from 21,026,742 records in the claims database of the Japan Medical Data Center Co. Ltd., Tokyo, Japan. The most frequent PTP sheet colors for 143 drugs were Sc (silver), Tc (white), Cc (blue), SLc (none), and Uc (silver). The prescribing pattern of 1000 randomly chosen prescriptions was analyzed. Database records of prescriptions without tablets (n = 69), including only one PTP tablet (n = 292), and those with lack of PDD prescription data (n = 388) were excluded. Eventually, 236 prescriptions were evaluated. Fourteen prescriptions (5.9%) had PTP sheets with five matching elements and 29 had with four matching elements (12.3%). This novel PDD database for information technology concept easily identified similar PTP sheets involved in prescriptions dispensed in 18 % of evaluated cancer patients. The concept seems to be applicable for preventing look-alike dispensing errors.

Enhancing T Cell Receptor Stability in Rejuvenated iPSC-Derived T Cells Improves Their Use in Cancer Immunotherapy

Limited T cell availability and proliferative exhaustion present major barriers to successful T cell-based immunotherapies and may potentially be overcome through the use of "rejuvenated" induced pluripotent stem cells derived from antigen-specific T cells (T-iPSCs). However, strict antigen specificity is essential for safe and efficient T cell immunotherapy. Here, we report that CD8αβ T cells from human T-iPSCs lose their antigen specificity through additional rearrangement of the T cell receptor (TCR) α chain gene during the CD4/CD8 double positive stage of in vitro differentiation. CRISPR knockout of a recombinase gene in the T-iPSCs prevented this additional TCR rearrangement. Moreover, when CD8αβ T cells were differentiated from monocyte-derived iPSCs that were transduced with an antigen-specific TCR, they showed monoclonal expression of the transduced TCR. TCR-stabilized, regenerated CD8αβ T cells effectively inhibit tumor growth in xenograft cancer models. These approaches could contribute to safe and effective regenerative T cell immunotherapies.

Abstract 2550: Generation of CAR-iPS-T cells expressing CD8β

Chimeric antigen receptor (CAR) is an artificial protein that provides HLA-independent antigen specificity to T cells. CAR-T therapy has shown remarkable clinical responses especially in hematologic malignancies. But this therapy needs cell preparation for each patient. That limits its applicability. We have reported regeneration of T cells from iPSCs (Cell Stem Cell 2013). This technology provides unlimited number of T cells, so CAR-T therapy using iPSCs can broadens its applicability. Regenerated T cells previously described in some reports including ours have some different characters from peripheral T cells. In particular, they express only CD8α, and do not express CD8β. We successfully generate CAR-iPS-T cells expressing CD8β with some modification of differentiation protocols. We assayed the function of CAR-iPS-T cells in view of the difference between CD8β positive and negative iPS-T cells. We found CD8β positive CAR-iPS-T cells showed enhanced function to suppress tumor progression compared with CD8β negative CAR-iPS-T cells in subcutaneous xenograft model. In vivo kinetics study revealed that CD8β positive CAR-iPS-T cells have superior function to traffic to target expressing tumor site and enhanced sustainability in vivo compared with CD8β negative CAR-iPS-T cells. These findings indicate that CD8β positive CAR-iPS-T cells may be a potent cell source for iPSC-based cancer immunotherapy.

Citation Format: Tatsuki Ueda, Shoichi Iriguchi, Yohei Kawai, Atsutaka Minagawa, Hiroyuki Miyoshi, Seitaro Terakura, Yasushi Uemura, Knut Woltjen, Yuzo Kodama, Hiroshi Seno, Yasumichi Hitoshi, Tetsuya Nakatsura, Koji Tamada, Shin Kaneko. Generation of CAR-iPS-T cells expressing CD8β [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2550.

Abstract 3585: T cell receptor-stabilized regenerated CD8ab cytotoxic T lymphocytes for cancer immunotherapy

The use of antigen-specific T cell derived induced iPSCs as a cell source for regeneration of cytotoxic T lymphocytes (CTLs) have advantages in rejuvenation profile, and reproducible number of CTLs. However for the safe and efficient regenerated T cell immunotherapy, strict antigen specificity is essential. Here we report CD8αβ T cells differentiated from T cell-derived iPSCs underwent additional rearrangement of the T cell receptor (TCR) α-chain gene at the CD4/CD8 double positive stage during in vitro differentiation and lost antigen specificity. CRISPR knockout of a recombinase gene in the T-iPSCs successfully prevented this additional TCR rearrangement. Moreover, when CD8αβ T cells were differentiated from non-T cell-derived but antigen-specific TCR-transduced iPSCs, they showed monoclonal expression of the transduced TCR. TCR stabilized regenerated CD8αβ T cells effectively inhibit tumor growth in xenograft cancer models. These approaches could contribute to safe and effective regenerative T cell immunotherapies.

Citation Format: Atsutaka Minagawa, Akitsu Hotta, Yohei Kawai, Yutaka Yasui, Yasushi Uemura, Masaki Yasukawa, Tetsuya Nakatsura, Shin Kaneko. T cell receptor-stabilized regenerated CD8ab cytotoxic T lymphocytes for cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3585.

Rise of iPSCs as a cell source for adoptive immunotherapy

Adoptive T cell transfer is a potentially effective strategy for treating cancer and viral infections. However, previous studies of cancer immunotherapy have shown that T cells expanded in vitro fall into an exhausted state and, consequently, have limited therapeutic effect. One way to overcome this obstacle is to use induced pluripotent stem cells (iPSCs) as a cell source for making effector T cells. In recent years, there have been several reports on generating effector T cells suitable for adoptive immunotherapy. The reported findings suggest that using iPSC technology, it may be possible to stably derive large numbers of juvenile memory T cells targeted to cancers or viruses. In this review, we describe a strategy for applying iPSC technology to immunotherapy and the characteristics of T cells derived from iPSCs. We also discuss how these technologies can be applied clinically in the future.

The citrus flavonoid, nobiletin, inhibits peritoneal dissemination of human gastric carcinoma in SCID mice

The flavonoid nobiletin (5,6,7,8,3',4'-hexamethoxyflavone), found in Citrus depressa Rutaceae, a popular citrus fruit in Okinawa, Japan, reportedly inhibits the production of pro-matrix metalloproteinase (proMMP)-1, 3, and 9 in rabbit synovial fibroblasts in vitro. In the present study, we demonstrated the inhibitory effects of nobiletin on the proliferation of the cancer cell line, TMK- 1, and its production of MMPs. In the SCID mouse model, we found that nobiletin inhibited the formation of peritoneal dissemination nodules from TMK-1. The enzymatic activity of MMP-9 expressed in culture medium obtained from a co-culture of TMK-1 and mouse fibroblastic cells was inhibited by nobiletin in a concentration-dependent manner. In the SCID mouse model, total weight of dissemination nodules was significantly lower in the treated group compared with the vehicle control group (0.07 g vs. 0.78 g, P = 0.0059). The total number of dissemination nodules was also significantly lower than in the vehicle control group (7.5 vs. 69.3 / body, P = 0.0001). These results suggest that nobiletin may be a candidate anti-metastatic drug for prevention of peritoneal dissemination of gastric cancer.

A patient of hypogonadotropic hypogonadism accompanied by growth hormone deficiency and decreased bone mineral density who attained normal growth

We present here a rare case of hypopituitarism accompanied by growth hormone (GH) deficiency and hypogonadotropic hypogonadism, in which the patient attained normal height but was of eunuchoid appearance. A 23-year-old man who had not reached puberty was referred to Saitama Medical School for hormonal evaluation. Basal hormonal data and hormone-stimulating tests revealed impaired secretion of GH, gonadotropins and adrenocorticotropic hormone (ACTH). Serum levels of testosterone, estrone, estradiol and estriol were all below the detectable ranges. The patient's plasma ACTH responded to corticotropin releasing hormone, but not to insulin-induced hypoglycemia. Serum GH showed a minimal response to GH-releasing hormone, but was unresponsive to insulin-induced hypoglycemia. Serum luteinizing hormone and follicle stimulating hormone did not respond to luteinizing hormone-releasing hormone. The results were compatible with a diagnosis of hypothalamic hypopituitarism. Magnetic resonance images of the brain showed a small anterior pituitary, an ectopic posterior lobe and transection of the pituitary stalk. Although the patient showed signs of hypopituitarism, he finally attained normal height, possibly because of failed epiphyseal maturation. His bone mineral density was markedly reduced to 0.647 g/cm2 in the lumbar spine; this level was 61.7% of the average level of healthy young males. Our findings were compatible with a recently advocated view that estrogen is important in promoting epiphyseal fusion and in determining bone density in males as well as females.

[The effects of exercise training on metabolic phases. With special reference to intraorganic fat and amino acids in Sprague-Dawley rats with streptozotocin diabetes]

We attempted to clarify the effects of aging and the difference between heavy and mild exercise training on the fat and amino acid (AA) systems of streptozotocin diabetic Sprague-Dawley rats in vivo. We exercised two groups of rats, both composed of juvenile and aged rats. The first group, however, consisted of diabetic rats only, the second of normal rats only. Both groups underwent mild training, 20 cm/s, or heavy training, 33 cm/s, for an hour a day, five times a week for four weeks. We looked for fat and amino acids in the serum, liver, red skeletal muscles and heart muscles at the pre- and post-training stages. The results were as follows: Although we observed decreased triglyceride (TG) levels in the serum, liver and intraskeletal muscles in the normal control group, similar decreases were also observed in the diabetic group undergoing insulin treatment with mild exercise training. On the other hand, we observed a clear increase in the rats subjected to heavy exercise training. This increase was particularly significant in the aged rats. There was, however, no significant change in the TG levels in the intraheart muscles of either the juvenile or aged rats, including the diabetic ones. Exercise training in the normal control group produced decreases in total AA, glycogenic AA, branched chain AA and ketogenic AA. Although there was no significant decrease in the TG levels in the serum, we could see clear signs of a decrease in the liver and the intraskeletal muscles. By contrast, the more the rats undergoing insulin treatment for diabetes were exercised, the greater the increase in the amount of AA in the livers and intraskeletal muscles. These changes were especially significant in the aged group. Consistent with previous reports, the diabetic groups produced different results for fat and AA in proportion to the intensity of exercise training and age of the rats. We also demonstrated that the differences were very small in the serum, but significant in the organs, livers and skeletal muscles. From the above findings, we have concluded that exercise training should play a major role in the treatment of diabetes in consideration not only of serum, but also transitions of the whole body's metabolic phases, including the intraorganic systems.

Higher excretion of urinary bound amino acids in infants: probably related to protein-anabolic effect of growth hormone

Concentrations of bound amino acids in urine were found to be markedly higher in infants than in children over 4 years of age. And it was also found that bound amino acid levels in plasma were increased in infants and young children than in adults. Urinary excretion of bound amino acids was increased in hypopituitary dwarf after one day of intramuscular injection of human growth hormone. A possibility was advanced that an increased excretion of bound amino acids of the overflow type observed in infants was due to active protein biosynthesis stimulated by growth hormone of which plasma levels have been reported to be high in infancy.

Hypoglycemia during prolonged exercise in normal men

Hypoglycemia (blood glucose less than 45 mg per deciliter [less than 2.5 mmol per liter]) occurred in seven of 19 healthy men who exercised to exhaustion on a cycle ergometer at 60 to 65 per cent of maximal aerobic power. The hypoglycemic subjects exercised for 15 to 70 minutes despite blood glucose levels of 25 to 48 mg per deciliter (1.4 to 2.7 mmol per liter), and their exhaustion time (mean +/- S.E.M., 142 +/- 15 minutes) was not significantly different from that of the euglycemic group (165 +/- 11). Plasma epinephrine was inversely related to blood glucose (P less than 0.01) and was three times higher in the hypoglycemic subjects (P less than 0.05). Glucose ingestion (40 or 80 g per hour) prevented the hypoglycemia and resulted in a smaller rise in plasma epinephrine but did not alter perceived exertion or consistently delay exhaustion. We conclude that hypoglycemia occurs in normal subjects during prolonged exercise and results in an exaggerated rise in plasma epinephrine. However, hypoglycemia fails to effect endurance, and its prevention does not consistently delay exhaustion.

[Study of weight-bearing changes of normal and abnormal feet by frontal tomography (author's transl)]

Roentogenographic examination with emphasis upon frontal tomography was applied to clarify the positional relationship between the calcaneus and talus, and to measure weight-bearing changes of these bones on normal and abnormal feet in frontal plane. studied were conducted on 30 left feet of normal adults, 18 left feet of normal children, and 37 feet of 19 children affected with cerebral palsy, and 19 feet with unilateral or bilateral foot disorders other than cerebral palsy. Statistical analysis of the in patients with diseases results gave the following results. The 30 feet of normal adults were without definite trend for internal or external rotation, medical or lateral shift, though the calcaneus in the sinus tarsi was found to lower to an average extent of 1.68 +/- 0.68mm. The 8 feet of normal children were also without definite trend of rotation or shift. The calcanei of some of children's flat feet with cerbral palsy were found to fluctuate markedly up and down and also medialy and laterally. But the weightbearing change was in most cases with cerebral palsy stayed within normal ranges. The 19 feet with disorders other than cerebral palsy were found to lie within the normal ranges of lowering, rotation and shift. The author's modification of Méary's method was able to be used quantitatively and qualitatively. This method showed that feet with calcaneus varus of calcaneus valgus deviate markedly from the normal feet based in the evidence of average precentage. The analysis by this quantitative method was found to agree well with that by frontal tomography.