T cell receptor gene-modified allogeneic T cells with siRNA for endogenous T cell receptor induce efficient tumor regression without graft-versus-host disease

Engineering CD3 subunits with endoplasmic reticulum retention signal facilitates allogeneic CAR T cell production

The success of autologous CAR T cell therapies has driven interest in developing off-the-shelf allogeneic CAR T cells as a scalable and readily available option for broader patient access. Most of the current approaches involve the knockout of T cell receptor (TCR) subunits via genome editing for preventing graft-versus-host disease (GvHD). However, clinical translation of these methods faces challenges due to manufacturing complexities and emerging safety concerns like unintended long deletions and chromosomal loss. In this study, we explored an alternative approach by engineering synthetic CD3 subunits containing an endoplasmic reticulum retention (ERR) signal to suppress TCR surface expression by disrupting its trafficking to the plasma membrane. We screened multiple CD3-ERR candidate designs to identify the construct with the highest efficacy in TCR downregulation. The selected candidate, CD3ζ-ERR, was further characterized, demonstrating its ability to minimize TCR-mediated activation and alloreactivity without affecting T cell phenotype, cell cycle and cytokine-induced expansion. Subsequent assays revealed that CD3ζ-ERR CD19 CAR T cells retained their CAR-mediated cytotoxic function against CD19+ malignant cells. This study presents an alternative approach for TCR downregulation that circumvents genome editing. By using a transgene compatible with conventional viral vector delivery, this approach holds promise for scalable clinical-grade manufacturing of allogeneic CAR T cell therapies.

Melanoma-associated antigen A4: A cancer/testis antigen as a target for adoptive T-cell receptor T-cell therapy

T-cell receptor (TCR) T-cell therapies are adoptive cell therapies in which patient cells are engineered to express TCRs targeting specific cancer antigens and infused back into the patient. Since TCR recognition depends on antigen presentation by the human leukocyte antigen system, TCRs can respond to intracellular antigens. Cancer/testis antigens (CTAs) are a large family of proteins, many of which are only expressed in cancerous tissue and immune-privileged germline sites. Melanoma-associated antigen A4 (MAGE-A4) is an intracellular CTA expressed in healthy testis and placenta, and in a range of cancers, including esophageal, head and neck, gastric, ovarian, colorectal, lung, endometrial, cervical, bladder, breast and prostate cancers; soft tissue sarcomas; urothelial and hepatocellular carcinomas; osteosarcoma; and melanoma. This expression pattern, along with the immunogenicity and potential role in tumorigenesis of MAGE-A4 make it a prime target for TCR T-cell therapy. We outline the preclinical and clinical development of TCR T-cell therapies targeting CTAs for treatment of solid tumors, highlighting the need for extensive preclinical characterization of putative off-target, and potential on-target but off-tumor, effects. We identified ten clinical trials assessing TCR T-cell therapies targeting MAGE-A4. Overall, manageable safety profiles and signals of efficacy have been observed, especially in patients with advanced synovial sarcoma, myxoid/round cell liposarcoma, ovarian, head and neck, and urothelial cancers, with one TCR T-cell therapy approved by the US Food and Drug Administration in August 2024. We also review the limitations, and strategies to enhance efficacy and improve safety, of these therapies, and summarize related immunotherapies targeting MAGE-A4.

Advancements in small interfering RNAs therapy for acute lymphoblastic leukemia: promising results and future perspectives

Acute lymphoblastic leukemia (ALL) is the most common type of cancer among children, presenting significant healthcare challenges for some patients, including drug resistance and the need for targeted therapies. SiRNA-based therapy is one potential solution, but problems can arise in administration and the need for a delivery system to protect siRNA during intravenous injection. Additionally, siRNA encounters instability and degradation in the reticuloendothelial system, off-target effects, and potential immune system stimulation. Despite these limitations, some promising results about siRNA therapy in ALL patients have been published in recent years, showing the potential for more effective and precise treatment, reduced side effects, and personalized approaches. While siRNA-based therapies demonstrate safety and efficacy, addressing the mentioned limitations is crucial for further optimization. Advancements in siRNA-delivery technologies and combination therapies hold promise to improve treatment effectiveness and overcome drug resistance. Ultimately, despite its challenges, siRNA therapy has the potential to revolutionize ALL treatments and improve patient outcomes.

Novel insights into TCR-T cell therapy in solid neoplasms: optimizing adoptive immunotherapy

Adoptive immunotherapy in the T cell landscape exhibits efficacy in cancer treatment. Over the past few decades, genetically modified T cells, particularly chimeric antigen receptor T cells, have enabled remarkable strides in the treatment of hematological malignancies. Besides, extensive exploration of multiple antigens for the treatment of solid tumors has led to clinical interest in the potential of T cells expressing the engineered T cell receptor (TCR). TCR-T cells possess the capacity to recognize intracellular antigen families and maintain the intrinsic properties of TCRs in terms of affinity to target epitopes and signal transduction. Recent research has provided critical insight into their capability and therapeutic targets for multiple refractory solid tumors, but also exposes some challenges for durable efficacy. In this review, we describe the screening and identification of available tumor antigens, and the acquisition and optimization of TCRs for TCR-T cell therapy. Furthermore, we summarize the complete flow from  laboratory to clinical applications of TCR-T cells. Last, we emerge future prospects for improving therapeutic efficacy in cancer world with combination therapies or TCR-T derived products. In conclusion, this review depicts our current understanding of TCR-T cell therapy in solid neoplasms, and provides new perspectives for expanding its clinical applications and improving therapeutic efficacy.