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Chimeric antigen receptor (CAR)-T therapy has demonstrated remarkable outcomes for B cell malignancies, however, its application for T cell lymphoma, particularly cutaneous T cell lymphoma (CTCL), has been limited. Barriers to effective CAR-T cell therapy in treating CTCL include T cell aplasia in autologous transplants, CAR-T product contamination with leukemic T cells, CAR-T fratricide (when the target antigen is present on normal T cells), and tumor heterogeneity. To address these critical challenges, innovative CAR engineering by targeting multiple antigens to strike a balance between efficacy and safety of the therapy is necessary. In this review, we discuss the current obstacles to CAR-T cell therapy and highlight potential targets in treating CTCL. Looking forward, we propose strategies to develop more powerful dual CARs that are advancing towards the clinic in CTCL therapy.

Chimeric antigen receptor (CAR)-based immunotherapy has shown considerable promise in cancer treatment by redirecting immune effector cells to recognize and eliminate tumor cells in an antigen-specific manner. While CAR-T cells bearing tumor-specific CARs have shown remarkable success in treating some hematological malignancies, their clinical application is limited by cytokine release syndrome, neurotoxicity, and graft-versus-host disease. In contrast, CAR–natural killer (NK) cells retain their multiple forms of natural anti-tumor capabilities without the pathological side effects and are compatible with allogeneic “off-the-shelf” application by not requiring prior activation signaling. Despite CAR-NK therapies showing promising results in hematological malignancies, they remain limited as effector cells against solid tumors. This is primarily due to the complex, immunosuppressive tumor microenvironment (TME), characterized by hypoxia, nutrient depletion, lactate-induced acidosis, and inhibitory soluble factors. Collectively, these significantly impair NK cell functionality. This review examines challenges faced by CAR-NK therapy in combating solid tumors and outlines strategies to reduce them. Barriers include tumor antigen heterogeneity, immune escape, trogocytosis-mediated fratricide, rigid structural and metabolic barriers in the TME, immunosuppressive factors, and defective homing and cell persistence of CAR-NK cells. We also emphasize the impact of combining other complementary immunotherapies (e.g., multi-specific immune engagers and immunomodulatory agents) that further strengthen CAR-NK efficacy. Finally, we highlight critical research gaps in CAR-NK therapy and propose that cutting-edge technologies are required for successful clinical translation in solid tumor treatment.

Neural crest cells make up a transient migratory population of cells found in all vertebrate embryos. Great advances have been made over the past 20 years in clarifying the molecular basis of neural crest induction and, although much still remains unclear, it appears that it is a process involving several factors acting at different stages of embryogenesis. In the future, an understanding of the precise mechanisms involved in orofacial development, even at the earliest stages, may well be of use to all clinicians interested in the management of these tissues.The present study was designed to determine if the early addition of noggin (a bone morphogenetic protein (BMP) antagonist) and/or the late addition of BMP4 would increase the expression of the transcription factors: Msx-1, Snail, Slug and Pax-7.This involved an assessment of the effects of early addition ( Days 0 to 3) of noggin and/or the late addition (Days 4 to 7) of BMP4 on the expression of the neural crest markers by human embryonic stem cells, co-cultured for eight days on a feeder layer of mouse PA6 cells.The expression of the neural crest markers Pax-7, Msx-1, Slug, and Snail by human embryonic stem cells is likely to be affected by the addition of noggin and BMP4. Not all of these effects will necessarily be significant. The late addition of BMP4 is likely to significantly increase the expression of Pax-7 by human embryonic stem cells (hESCs), when compared with the effects of co-culturing with stromal cell-derived inducing activity, alone. The early addition of noggin and the late addition of BMP4 are likely to significantly increase the expression of Msx-1 by hESCs, when compared with the late addition of BMP4, alone. The hESC results support those from animal ESC studies that the late addition of BMP4, especially, may result in the differentiation of neural crest precursors.

Objective: The objective of this study was to determine the potential of human embryonic stem (hES) cells to provide an in vitro model of human extraembryonic endoderm development. Methods: The hES cell line HES-2 was propagated in Dulbecco’s modification of Eagle’s medium (DMEM) in the presence of 20% fetal calf serum (FCS) on a mouse embryonic fibroblast feeder layer. Clumps of approximately 50–100 cells were transferred to fresh DMEM and FCS and grown as embryoid bodies (EBs) in suspension culture. EBs were subjected to immunohistochemistry for endodermal, ectodermal and mesodermal specific markers and immunoreactivity analysed by confocal microscopy and on cryosections. Results: HES-2 cells reproducibly formed spherical EBs after 2–3 days in suspension culture as clumps. EBs continued to expand and by 7 days had commenced cavitation in a highly reproducible and organised fashion. Culture periods longer than 10 days led to cystic structures displaying inconsistent morphological organisation. Immunolocalisation of anti-α-fetoprotein-, anti-neurofilament- and anti-CD31-specific antibodies at 7 days of culture provided evidence of regional differentiation of endodermal, ectodermal and mesodermal derivatives in cavitating EBs. Further, of 10 cavitating EBs analysed at 7 days of culture, all displayed immunolocalisation of anti-pan-keratin-, anti-CK8- and anti-α-fetoprotein-specific antibodies to a peripheral cellular layer, suggestive of yolk sac visceral endoderm (VE) formation. Conclusion: Cavitation, the presence of regionalised cell lineage-specific immunoreactivity and the development of a VE-like peripheral cell layer demonstrate that the HES-2 hES cell line can be induced to undergo EB formation and provide scope to study early human primitive endoderm and yolk sac VE development.

Rodent models and immortalized or genetically modified cell lines are frequently used—but have limited utility—for studying human prostate development and maturation. Using rodent mesenchyme to establish reciprocal mesenchymal-epithelial cell interactions with human embryonic stem cells (hESCs), we generated human prostate tissue expressing prostate-specific antigen (PSA) within 8–12 weeks. This human prostate model shows species-conserved signalling mechanisms that could extend to integumental, gastrointestinal and genital tissues.

Androgens acting via the androgen receptor bring about stimulation and maintenance of spermatogenesis. If mutations in the androgen-receptor gene interfere with the receptor's function, this effect may partly account for impaired spermatogenesis. We aimed to find out whether expansion of a trinucleotide repeat in the androgen-receptor gene is associated with male infertility. We analysed 67 coded semen and blood samples from a predominantly white group of male infertility patients and controls. Clinical analyses included cause of infertility, sperm count, and reproductive hormone concentrations. Analysis of trinucleotide (CAG) repeat length and point mutations in the androgen-receptor gene was done by PCR, single-stranded conformational polymorphism, and DNA sequencing. Screening and characterisation of the androgen-receptor gene in 35 patients and 32 controls showed no point mutations in the gene. 30 of the infertile patients had idiopathic azoospermia or oligozoospermia, and these men had significantly longer CAG repeat tracts than controls (mean 23·2 [SE 0·7] vs 20·5 [0·3], p=0·0001). The odds of having CAG repeat lengths of 20 were six-fold higher for fertile men than for men with a spermatogenic disorder. Our results indicate a relation between CAG repeat length in the androgen-receptor gene and the risk of defective spermatogenesis. With the use of intracytoplasmic sperm injection, this mutation could be inherited, possibly leading to an increase in male infertility in future generations. Should further elongation of the CAG repeat occur in these future generations, there is an added risk of increased severity of male infertility, and potentially an increased incidence of neurodegenerative disease.

Nuclear transfer (NT) experiments in mammals have demonstrated that adult cells are genetically equivalent to early embryonic cells and the reversal of the differentiated state of a cell to another that has characteristics of the undifferentiated embryonic state can be defined as nuclear reprogramming. The feasiblity of interspecies somatic cell NT (iSCNT) has been demonstrated by blastocyst formation and the production of offspring in a number of studies. Embryo and oocyte availability is a major limiting factor in conducting NT to obtain, blastocysts for both reproductive NT studies in genetically endangered animals and in embryonic stem cell derivation for species such as the horse and human. One approach to generate new embryonic stem cells in human as disease models, or in species where embryos and oocytes are not widely available, is to use oocytes from another species. Utilization of oocytes for recipient cytoplasts from other species that are accessible and abundant, such as the cow and rabbit, would greatly benefit ongoing research on reprogramming and stem cell sciences. The use of iSCNT is an exciting possibility for species with limited availability of oocytes as well as for endangered or exotic species where assisted reproduction is needed. However, the mechanisms involved in nuclear reprogramming by the oocyte are still unknown and the extent of the \"universality\" of ooplasmic reprogramming of development remains under investigation.[PUBLICATION ABSTRACT]

Embryonic stem cells Techniques for reprogramming adult cells are much sought after for creating cells to genetically match those of patients. Such embryonic stem cells might be used therapeutically without immune rejection. One reprogramming method is somatic cell nuclear transfer, where an adult cell nucleus is inserted into an oocyte that has its own nucleus removed. An early (blastocyst) stage embryo is induced to form, from which embryonic stem cells are teased out and cultured. Previously, this was possible only in mice. Now Byrne et al . have succeeded with the technique using primate adult fibroblasts as the start point. They generated two embryonic stem cell lines from 304 oocytes taken from 14 rhesus monkeys. This success suggests that this approach might be suitable for generating patient-derived embryonic stem cells. A validation paper accompanies this package on the Nature web site. The colorized cover image shows an egg just prior to enucleation. The egg is held by a holding pipette and to the right, a sharp enucleation pipette points towards the nucleus. Arising from: J. A. Byrne et al. Nature450, doi: 10.1038/nature06357 (2007) Somatic cell nuclear transfer (SCNT) into enucleated oocytes has emerged as a technique that can be used to derive mouse embryonic stem cell lines with defined genotypes. In this issue Byrne et al. 1 report the derivation of two SCNT Rhesus macaca male stem cell lines designated CRES-1 and CRES-2. Molecular studies detailed in their paper provides supporting evidence that the chromosome complement of CRES-1 and CRES-2 was genetically identical to the male cell donor nucleus and that the mitochondrial DNA originated from different recipient oocytes. In this validation paper, we independently confirm that both stem cell lines were indeed derived by SCNT.