GPRC5D Chimeric Antigen Receptor (CAR): A Comprehensive Guide and Our Service & Product Introduction

The global market for multiple myeloma immunotherapy is growing rapidly, driven by the high unmet medical need for relapsed/refractory patients. GPRC5D, as a novel and promising target, has attracted significant attention from biopharmaceutical companies and research institutions. The increasing number of clinical trials and the promising efficacy data of GPRC5D-targeted therapies (including CAR-T cells and bispecific antibodies) are expected to drive the demand for GPRC5D CAR expression plasmid vectors. RGBiotech’s product portfolio and custom services are designed to meet the growing needs of researchers and biopharmaceutical companies in this fast-growing field, providing reliable tools to accelerate the development of GPRC5D-targeted therapies.

With years of experience in CAR plasmid vector development and customization, RGBiotech has established a professional team of scientists with in-depth expertise in GPRC5D biology and CAR design. Our products are optimized based on the latest research progress, ensuring high expression efficiency, stability, and functionality. RGBiotech offers standard plasmid products, custom vector construction, and technical support, to help you overcome research challenges and accelerate your research progress. Our strict quality control standards and competitive pricing make us the preferred partner for GPRC5D CAR research.

If you are interested in our GPRC5D CAR expression plasmid vector products or custom services, or have any questions about GPRC5D CAR research, please contact us at admin@rgbiotech.com. Our professional team will provide you with detailed product information, technical support, and customized solutions to meet your research needs.

Our GPRC5D CAR Expression Plasmid Vector Products and Custom Services

RGBiotech offers a comprehensive range of GPRC5D CAR expression plasmid vector products, covering all generations of GPRC5D CAR (1st to 5th generation), to meet the diverse needs of researchers and biopharmaceutical companies in research. In addition, we provide professional custom plasmid vector construction services, tailored to your specific research requirements, to accelerate your GPRC5D CAR research and development process.

We provide GPRC5D CAR expression plasmids for 1st to 5th generation CARs, each with optimized structural designs to meet different research needs.
1) 1st generation: Contains only the CD3ζ intracellular signaling domain, suitable for basic research on GPRC5D recognition and T cell activation.
2) 2nd generation: Adds one costimulatory domain (e.g., CD28, 4-1BB) to enhance T cell proliferation and persistence, the most widely used generation in preclinical research.
3) 3rd generation: Incorporates two costimulatory domains (e.g., CD28+4-1BB, CD28+OX40) to further improve anti-tumor efficacy and T cell survival.
4) 4th generation (armored CAR): Modified from 2nd generation CARs to constitutively or inducibly express cytokines (e.g., IL-15, IL-21), enhancing immune cell activation and tumor infiltration.
5) 5th generation (switchable CAR): Equipped with a controllable switch (e.g., small molecule-induced dimerization) to regulate CAR activity, improving safety and reducing off-target toxicities.

Product Features

Product Advantages

Product Applications

Custom Plasmid Vector Construction Services

In addition to our standard products, we offer professional custom GPRC5D CAR plasmid vector construction services to meet your unique research needs. We ensure fast turnaround times and strict quality control for all custom vectors, helping you accelerate your research progress.
1) Custom CAR Design: Design and construction of GPRC5D CAR plasmids with custom scFv/VHH sequences, hinge/spacer regions, transmembrane domains, costimulatory domains, and signaling domains.
2) Vector Backbone Customization: Modification of vector backbones (non-viral, lentiviral, retroviral, AAV) to include custom elements, such as inducible promoters, suicide genes, or cytokine expression cassettes.
3) Vector Engineering: Construction of dual-target CAR plasmids (e.g., GPRC5D + BCMA), switchable CAR plasmids, or armored CAR plasmids expressing cytokines or immune checkpoint inhibitors.
4) Full Technical Support: Our team of experienced scientists provides full technical support throughout the customization process.

Introduction of GPRC5D

GPRC5D (G-protein coupled receptor family C group 5 member D) is an orphan G-protein coupled receptor (GPCR) encoded by the GPRC5D gene, which is located on human chromosome 12p13 (HGNC: 13310, MIM: 607437). The gene has multiple secondary accessions including Q3KNV3, Q7Z5J9, and Q8TDS6, with the primary UniProt accession Q9NZD1 for its encoded protein in Homo sapiens. The open reading frame (ORF) of GPRC5D is approximately 1038 bp, encoding a protein consisting of 345 amino acids. As a member of the class C GPCR family, GPRC5D shares typical structural characteristics of this family while exhibiting unique expression and functional features that make it a promising target for therapeutic development, especially in oncology.

The GPRC5D protein is a multi-pass membrane protein primarily localized to the cell membrane, with additional distribution in extracellular exosomes and receptor complexes. Its structural topology includes five transmembrane helical domains, with alternating extracellular and cytoplasmic topological domains: the N-terminal extracellular domain (residues 1-27), followed by transmembrane domains 1-5 (residues 28-48, 64-84, 94-114, 124-144, 168-188) and cytoplasmic domains (residues 49-63, 115-123) between them, as well as an extracellular loop between transmembrane domains 4 and 5 (residues 145-167). This multi-domain structure is critical for its potential receptor function and interaction with downstream signaling molecules, though its natural ligand remains unknown to date.

GPRC5D is a G-protein coupled receptor involved in the regulation of hard keratin expression and is likely to play an important role in the development of hair and nails. At the molecular level, it exhibits G protein-coupled receptor activity and protein kinase activator activity, participating in intracellular signal transduction pathways that regulate cell function. Recent studies have further revealed its potential role in tumor biology, particularly in the progression of multiple myeloma, where its high and selective expression on tumor cells makes it a key target for targeted therapy.

GPRC5D exhibits a relatively restricted tissue expression pattern. At the protein level, it is primarily detected in epithelial structures of the skin and tongue, as well as in immune cells with a plasma cell phenotype. In the immune system, GPRC5D is predominantly expressed in plasma cells but has little to no expression in normal B cells, T cells, natural killer cells, monocytes, granulocytes, and bone marrow progenitors, distinguishing it from other myeloma-associated antigens such as CD38 and BCMA which have a broader expression profile. Low levels of GPRC5D mRNA have also been detected in the motor neurons of the inferior olivary nucleus, though its function in these cells remains unclear. This restricted expression pattern minimizes the potential for off-target toxicities in targeted therapy.

The most well-established association of GPRC5D is with multiple myeloma (MM), a genetically complex and heterogeneous hematological malignancy with a 5-year survival rate of approximately 60%. GPRC5D is highly and selectively expressed on the surface of myeloma cells, including relapsed/refractory multiple myeloma (RRMM) cells, even in patients who have failed BCMA-targeted therapies due to antigen escape. This makes GPRC5D a crucial alternative target for the treatment of RRMM. Additionally, its involvement in hair and nail development suggests potential associations with dermatological conditions, though research in this area remains limited. The selective expression of GPRC5D on tumor cells positions it as an ideal target for CAR-T cell therapy and other targeted treatment strategies.

Introduction of GPRC5D Chimeric Antigen Receptor (CAR)

GPRC5D Chimeric Antigen Receptor (CAR) is a genetically engineered receptor designed to redirect immune cells (primarily T cells and NK cells) to specifically recognize and eliminate GPRC5D-expressing tumor cells, particularly myeloma cells. Structurally, a GPRC5D CAR typically consists of four core components: an extracellular antigen recognition domain (usually a single-chain variable fragment, scFv, or single domain antibody, VHH, targeting GPRC5D), an extracellular hinge/spacer region for flexibility and stability, a transmembrane domain anchoring the receptor to the cell membrane, and intracellular signaling domains that activate immune cell function upon antigen binding. The continuous evolution of CAR generations has significantly improved the efficacy and safety of GPRC5D CAR-based therapies.

Current Research Achievements

Recent years have witnessed remarkable progress in GPRC5D CAR research, with numerous preclinical and clinical studies demonstrating promising efficacy and manageable safety profiles.
1) OriCAR-017: A GPRC5D-targeted CAR-T cell therapy developed by Oricell Therapeutics, which received FDA IND clearance in 2024 and NMPA IND approval in 2023. Clinical data from the POLARIS study showed a 100% overall response rate (ORR) and 80% stringent complete response (sCR) in 10 RRMM patients, with 100% minimal residual disease (MRD) negativity at day 28. The therapy was well-tolerated, with no ICANS or cerebellar disorder, and only Grade 1/2 CRS that resolved rapidly.
2) RD118: A fully human GPRC5D-targeted CAR-T therapy evaluated in a Phase I clinical trial in China. With a median follow-up of 17.0 months, the ORR reached 94.4%, with 72.2% of patients achieving CR/sCR. The median progression-free survival (PFS) was 18.2 months, and 85.7% of patients who had previously received BCMA CAR-T therapy responded to treatment. Safety was manageable, with mostly Grade 1-2 CRS and only 1 case of Grade 3 ICANS.
3) FT555: A GPRC5D CAR-NK cell therapy derived from iPSCs, expressing high levels of hnCD16 (>90%) and IL-15RF (>90%) with CD38 knocked out, showing promising preclinical activity in myeloma models.
4) Preclinical studies: Multiple preclinical models have confirmed that GPRC5D CAR-T/NK cells can specifically recognize and lyse GPRC5D-expressing myeloma cells, with enhanced proliferation and persistence compared to traditional therapies. Novel CAR designs, such as TCR-ABR (TCR-fused antigen binding receptor) targeting GPRC5D, have also shown potential by reprogramming the intact TCR complex for HLA-independent tumor recognition.

Approved Drugs

To date, there are no approved GPRC5D CAR-T cell therapy drugs globally. However, several GPRC5D-targeted therapies are in advanced clinical development stages, including CAR-T cell therapies and bispecific antibodies.
1) OriCAR-017 (Oricell Therapeutics): Phase I/II clinical trials ongoing in the US and China for the treatment of RRMM.
2) RD118: Phase I clinical trial completed in China, with plans for further clinical development to validate long-term efficacy and safety.
3) MCA-RH109, BMS-986393: GPRC5D-targeted CAR-T therapies in early-phase clinical trials, showing preliminary efficacy in RRMM patients.
4) Bispecific antibodies: Talquetamab and FOR46 (forimtamig), which target GPRC5D and CD3, have shown promising efficacy in early-phase trials, with ORR ≥64% in RRMM patients, providing a complementary approach to CAR-T therapy.
The rapid progress in clinical development suggests that GPRC5D CAR therapies are likely to become a new standard of care for RRMM in the near future, particularly for patients who have relapsed after BCMA-targeted therapies.

Research Hotspots

Current research hotspots in GPRC5D CAR field focus on optimizing efficacy, improving safety, and expanding application scope.
1) Novel CAR designs: Development of fully human scFv/VHH-based CARs to reduce immunogenicity and improve persistence, as well as TCR-ABR and other modified CAR structures for enhanced tumor recognition.
2) Combination therapies: Exploring combinations of GPRC5D CAR-T therapy with immune checkpoint inhibitors, epigenetic modifiers, or other anti-myeloma drugs to overcome tumor microenvironment immunosuppression and improve therapeutic efficacy.
3) Allogeneic CAR-T/NK cells: Development of off-the-shelf allogeneic GPRC5D CAR-T/NK cells (e.g., iPSC-derived CAR-NK cells like FT555) to address the limitations of autologous CAR-T therapy, such as insufficient autologous T cells and long manufacturing time.
4) Dual-target CARs: Design of dual-target CARs targeting GPRC5D and other myeloma-associated antigens (e.g., BCMA, CD38) to prevent antigen escape and improve treatment durability.
5) Toxicity management: Investigation of mechanisms underlying GPRC5D-related toxicities (e.g., dermatologic and oral adverse events) and development of strategies to mitigate these toxicities while maintaining efficacy.

Research Difficulties & Challenges

Despite significant progress, GPRC5D CAR research still faces several difficulties and challenges that need to be addressed.
1) Antigen escape: Similar to other targeted therapies, GPRC5D-targeted CAR therapies may face the problem of antigen escape, where tumor cells downregulate GPRC5D expression to evade immune recognition. This highlights the need for dual-target or multi-target CAR designs and combination therapies.
2) Toxicity issues: GPRC5D expression in normal skin and tongue epithelial cells can lead to dermatologic and oral adverse events, such as nail changes and rash, which are consistent across clinical trials of GPRC5D-targeted therapies. Rare cerebellar events have also been reported in some CAR-T trials, and the underlying mechanisms remain unclear.
3) CAR-T cell persistence and exhaustion: Long-term persistence of GPRC5D CAR-T cells is critical for sustained anti-tumor efficacy, but T cell exhaustion in the tumor microenvironment remains a major challenge. Strategies to enhance CAR-T cell persistence, such as optimizing costimulatory domains and combining with cytokines, are actively being explored.
4) Manufacturing and scalability: Autologous CAR-T therapy has complex manufacturing processes, long production cycles, and high costs, limiting its widespread application. The development of allogeneic CAR-T/NK cells and efficient manufacturing platforms is essential to address these issues.
5) Clinical trial limitations: Many current clinical trials have small sample sizes, short follow-up periods, and regional limitations (e.g., single-country studies), making it difficult to fully evaluate long-term efficacy and safety in diverse patient populations.

Frequently Asked Questions (FAQs)

Q: What is the difference between different generations of CARs?
A: The main difference lies in the number and type of intracellular signaling domains. 1st generation CARs have only CD3ζ; 2nd generation adds one costimulatory domain; 3rd generation adds two costimulatory domains; 4th generation (armored CARs) express cytokines; 5th generation (switchable CARs) have controllable activity. Each generation has distinct advantages in terms of T cell activation, proliferation, persistence, and safety.

Q: How to choose the appropriate GPRC5D CAR generation for my research?
A: For basic research on GPRC5D recognition, 1st generation is sufficient. For preclinical efficacy evaluation, 2nd or 3rd generation is recommended due to enhanced T cell persistence and anti-tumor activity. 4th generation is suitable for research on overcoming tumor microenvironment immunosuppression, while 5th generation is ideal for studies focusing on safety and controllability.

Q: How to detect GPRC5D CAR expression in cells?
A: CAR expression can be detected using flow cytometry with fluorescently labeled GPRC5D protein, or anti-4GS-linker antibody or by utilizing the fluorescent tag integrated into the plasmid vector (e.g., GFP, RFP). Western blotting can also be used to confirm CAR protein expression at the molecular level.

Q: What are the main factors affecting GPRC5D CAR-T cell efficacy?
A: Key factors include CAR expression level, binding affinity to GPRC5D, T cell phenotype (e.g., naive vs. memory T cells), T cell persistence, and the tumor microenvironment (e.g., immunosuppressive cells, cytokines).

Q: How to choose the appropriate vector backbone for GPRC5D CAR research?
A: For transient expression or in vitro studies, non-viral plasmids are suitable. For stable transduction of primary T/NK cells, lentiviral vectors are preferred due to high transduction efficiency and stable integration. Retroviral vectors are suitable for dividing cells, while AAV vectors are ideal for in vivo applications with low immunogenicity.

Q: How to store the plasmid vectors?
A: Plasmid vectors should be stored at -20°C or -80°C. Avoid repeated freeze-thaw cycles, which can damage the plasmid DNA.

Q: What should I do if the plasmid transfection efficiency is low?
A: Possible reasons include low plasmid purity, inappropriate transfection reagent, or unsuitable cell state. Solutions: Use high-purity plasmids (A260/A280 1.8-2.0), optimize transfection reagent dosage and ratio, and ensure cells are in good growth state (confluency 70-80%) before transfection.

Q: What is the difference between Ampicillin and Puromycin selection markers?
A: Ampicillin is used for selection in prokaryotic cells (e.g., E. coli), while Puromycin is used for selection in eukaryotic cells (e.g., T cells, 293T cells). Choose the appropriate marker based on your experimental system.

Q: How to confirm the correctness of the custom plasmid?
A: We provide full sequence verification (Sanger) for custom plasmids, and a QC report documenting sequence accuracy. You can also perform restriction enzyme digestion and agarose gel electrophoresis to verify the plasmid size.

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