Kim, Gloria B.

ABSTRACT As a principal metabolite of ginsenosides, compound K (CK) exhibits remarkable antioxidant, anti‐inflammatory, antidiabetic, and anticancer bioactivities. However, CK is naturally scarce in ginseng and its industrial application is limited by the lack of efficient deglycosylating enzymes for large‐scale CK bioproduction. Here, we report a synthetic biology‐driven approach for high‐yield CK production via recombinant β‐glycosidase‐mediated bioconversion of the polar ginsenoside Rb1. The β‑glycosidase‐encoding gene was introduced into Escherichia coli BL21 (DE3), and the resulting engineered strain produced 2.1 g/L β‑glycosidase in shake flasks and 10.1 g/L in a 5‐L fermentor. The crude β‐glycosidase exhibited excellent enzymatic activity; at a concentration of 1.5 g/L, it converted 95% of the Rb1 substrate (initial concentration 10 g/L) to CK within 4 h. In vitro studies demonstrated CK's high cytocompatibility and potent anti‐aging effects, including suppression of reactive oxygen species ( via upregulation of superoxide dismutase, catalase, and glutathione peroxidase), enhanced collagen I, Ⅲ and elastin synthesis, and matrix metalloproteinase‐1 inhibition. These findings highlight CK as a promising candidate for anti‐wrinkle formulations, supported by the feasibility of scalable bioproduction.

Abstract The success of Chimeric Antigen Receptor (CAR) T cell therapy is heavily dependent on the quality of the final cellular product. Current expansion protocols often rely on reagents that require removal from cell culture media, posing logistical challenges in manufacturing, and can also lead to terminal differentiation. Here, we evaluate the use of a soluble, bead-free T cell activator, T cell expansion protein (T-CEP), as a streamlined alternative for generating potent CAR-T cells. Human T cells were activated with T-CEP or known T cell activators (Dynabeads and TransAct) and transduced with either CD19 or interleukin-13 (IL-13) mutein (tetravariant-13; TV-13)-based CAR lentiviral vectors. Our results demonstrate that T-CEP supports robust CAR-T cell expansion and achieves transduction efficiencies comparable to commercial reagents for both types of CAR-T cells. Notably, T-CEP significantly favored the expansion of CD8 + T cells, yielding an enhanced CD27 + phenotype and a lower CD4:CD8 ratio compared to TransAct. Cytotoxicity assays confirmed that T-CEP-expanded CAR-T cells possess cytolytic function equivalent to commercial reagents for both CARs, while exhibiting lower levels of inflammatory cytokine secretion. In summary, T-CEP represents a competitive alternative to existing expansion agents, as it does not require its removal during CAR-T manufacturing and generates a CD8 + dominant, less-differentiated phenotype without compromising efficacy. Key Points T-CEP is a soluble, bead-free activator that streamlines CAR-T manufacturing by eliminating the need for reagent removal from cultures. T-CEP consistently yields a desirable CD27 + CD8 + phenotype with a moderate inflammatory profile compared to industry-standard expanders.

Abstract Background: Clear cell renal cell carcinoma (ccRCC), metastatic castration-resistant prostate cancer (mCRPC), and glioblastoma (GBM) are treatment-refractory tumors marked by high TGF-β1, a master suppressor of antitumor immunity and antigen presentation. Pharmacologic methylseleninic acid (MSA) potently inhibits TGF-β1, PD-L1, and VEGF without significant off-target toxicity. FN14, the TWEAK receptor and a metastasis driver, is selectively overexpressed in these malignancies, making it a high-specificity CAR-T target. Methods: We developed second-generation anti-FN14 CARs with CD28 or 4-1BB costimulation and CD3ζ signaling and lentivirally transduced them into human CD4+/CD8+ T cells. Cytotoxicity against FN14+ ccRCC, mCRPC, GBM lines and patient-derived tumors was measured using LDH release and xCELLigence assays. Effector function was assessed by intracellular cytokines, phenotyping, and multiplex analysis. MSA was tested at physiologic concentrations to evaluate effects on CAR-T viability, metabolism, function, and tumor susceptibility. Results: Anti-FN14 CAR-T cells mediated rapid, antigen-specific lysis across all tumor types, achieving >50% specific lysis at an E:T ratio of 1:1. MSA (2.5-5 µM) reduced tumor PD-L1 and TGF-β by >40% and improved CAR-T metabolic activity, enhancing IL-2 and IFN-γ secretion. Manufacturing CAR-T cells with MSA (2.5 µM) increased cytotoxicity and persistence versus controls (p < 0.01). MSA’s effects were dose- and schedule-dependent at clinically compatible concentrations without detectable off-target toxicity. Conclusion: MSA augments anti-FN14 CAR-T cytotoxicity, metabolic fitness, and sustained effector function by suppressing tumor-derived TGF-β1 and PD-L1 and directly enhancing CAR-T activity. As a clinically relevant TGF-β1 inhibitor and active seleno-L-methionine metabolite, MSA represents a readily translatable strategy to reduce CAR-T exhaustion and improve efficacy in TGF-β-rich solid tumors. Citation Format: Gloria B. Kim, Obed B. Amissah, Casey R. Ager, Yousef Zakharia, Youcef M. Rustum. Methylseleninic acid enhances anti-FN14 CAR-T cell effector function and redirects cytotoxicity against TGF-β-rich kidney, prostate, and brain tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6496.

Abstract Background: Clear cell renal cell carcinoma (ccRCC), metastatic castration-resistant prostate cancer (mCRPC), and glioblastoma (GBM) are highly treatment-refractory tumors characterized by elevated TGF-β1, a key suppressor of antitumor immunity and antigen presentation. Because CAR-T cells infiltrating these tumors experience persistent physiologic TGF-β exposure, assessing CAR-T functional resilience across increasing TGF-β concentrations is critical for determining therapeutic feasibility. Methylseleninic acid (MSA), a pharmacologic selenium compound, potently inhibits TGF-β1, PD-L1, and VEGF with minimal off-target toxicity. FN14, the TWEAK receptor and a metastasis driver, is selectively overexpressed in these malignancies, making it a high-specificity CAR target. Methods: We developed second-generation anti-FN14 CARs containing CD28 or 4-1BB costimulatory domains and a CD3ζ signaling motif, then lentivirally transduced into primary human CD4+ and CD8+ T cells. Cytotoxicity against FN14+ ccRCC, mCRPC, GBM lines and patient-derived cells was assessed using LDH release and xCELLigence assays. Effector function was evaluated through intracellular cytokine profiling, multiplex analysis, and phenotypic characterization by flow cytometry. CAR-T persistence in TGF-β-rich conditions was measured using CCK-8 proliferation assays, and Ki-67 and activation/exhaustion markers (PD-1, CXCR3) in the presence of 0-10 ng/mL TGF-β. MSA’s immunomodulatory and synergistic effects were tested at physiologically concentrations to measure impacts on CAR-T viability, metabolic activity, cytokine secretion, and tumor cell susceptibility. Results: Anti-FN14 CAR-T cells mediated rapid, antigen-specific lysis across all tumor types, achieving >50% specific killing at a 1:1 E:T ratio. MSA (2.5-5 µM) reduced tumor PD-L1 and TGF-β expression by >40% and enhanced CAR-T metabolic activity, IL-2, and IFN-γ secretion. CAR-T cells maintained comparable proliferation and activation in 0-5 ng/mL TGF-β, indicating that antigen-driven signaling counteracted low-to-moderate TGF-β-mediated suppression. Ex vivo CAR-T manufacturing with MSA (2.5 µM) improved cytotoxicity and persistence versus untreated CAR-T cells (p < 0.01). MSA’s effects were dose- and schedule-dependent and remained within human-relevant exposure ranges without detectable toxicity. Conclusion: MSA enhances anti-FN14 CAR-T cytotoxicity, metabolic fitness, and sustained effector activity by suppressing tumor-derived TGF-β1 and PD-L1 and by directly improving CAR-T functional capacity. Consistent with this mechanism, physiological TGF-β levels (0-5 ng/mL) did not significantly impair CAR-T proliferation or activation, demonstrating intrinsic resilience of FN14 CAR-T cells in TGF-β-rich environments. As a clinically relevant TGF-β1 inhibitor and active metabolite of seleno-L-methionine, MSA represents a readily translatable strategy to reduce CAR-T exhaustion and enhance efficacy in TGF-β-rich solid tumors including ccRCC, mCRPC, and GBM. Citation Format: Obed B. Amissah, Casey Ager, Yousef Zakharia, Youcef M. Rustum, Gloria B. Kim. Anti-FN14 CAR-T cells overcome TGF-β-mediated suppression, and their synergy with methylseleninic acid enhances cytotoxicity and effector function in kidney, prostate, and brain tumors [abstract]. In: Proceedings of the AACR Immuno-Oncology Conference (AACR IO): Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2026 Feb 18-21; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2026;14(2 Suppl):Abstract nr C010.