Augert, A. | bioRxiv Science

bioRxiv2026

Nanobody MET CAR T cells show efficacy in solid tumors

BackgroundMET overexpression is associated with poor prognosis in many solid tumors due to its central role in tumor survival, invasion, metastasis, and chemoresistance. While targeting MET with antibody-drug conjugates has shown promising results, engineered cellular immunotherapeutic approaches have not been extensively explored. Compared to conventional single-chain variable fragments (scFv), naturally occurring single-domain antibodies consisting of variable heavy chains only (VHH or nanobodies) are smaller, retain high specificity, and exhibit remarkable biochemical stability. In this study, we tested the efficacy of MET-targeting VHH-CAR-T (chimeric antigen receptor T cells). MethodsWe generated a panel of VHH-CAR-Ts using mRNA electroporation. VHH-CAR-T cells were evaluated in functional assays including cell binding avidity, cytokine production profiles, hydrogel microwell-based cellular kinetics, and in vitro cytotoxicity. We also assessed the therapeutic efficacy of VHH-CAR-T in an in vivo mouse model of metastatic triple negative breast cancer (TNBC). ResultsAmong the tested VHH, we identified those with intermediate avidity as most effective for in vitro tumor killing. VHH-CAR-Ts with CD28 costimulatory domains demonstrated augmented cytotoxicity with favorable selectivity, requiring a minimum antigen density threshold for activation. Mechanistically, VHH-CAR-Ts demonstrated low tonic signaling, high avidity, potent cytokine production, and rapid tumor killing kinetics. When administered in an mRNA format, VHH-CAR-Ts exhibited potent and prolonged control of tumor growth in an in vivo metastatic model of TNBC. ConclusionTaken together, these results demonstrate that VHH-CAR-Ts exhibit robust MET specificity and potent therapeutic efficacy both in vitro and in vivo. Thus, VHH-CAR-T cell therapy represents a promising immunotherapeutic strategy for targeting MET-overexpressing solid tumors. What is already known on this topicMET signaling is an important contributor to the aggressiveness of many solid tumors, and targeting MET by antibody-drug conjugates has shown efficacy and safety. Targeting MET by CAR-T cells has been under study, though with limited potency. What this study addsThis study is the first to demonstrate effectiveness of anti-MET VHH-CAR-T cells. Compared with other antigen binding domains, VHH-incorporated CAR-T cells show low tonic signaling, a favorable cytokine profile, and potent tumor killing. How this study might affect research, practice or policyWith the multiple advantages of VHHs including small size, stability, and low potential for tonic signaling, VHH-CAR-T cells represent a promising approach for CAR-T design against solid tumors.

immunology↗

bioRxiv2024

MAX inactivation deregulates the MYC network and induces neuroendocrine neoplasia in multiple tissues

The MYC transcription factor requires MAX for DNA binding and widespread activation of gene expression in both normal and neoplastic cells. Surprisingly, inactivating mutations in MAX are associated with a subset of neuroendocrine cancers including pheochromocytoma, pituitary adenoma and small cell lung cancer. Neither the extent nor the mechanisms of MAX tumor suppression are well understood. Deleting Max across multiple mouse neuroendocrine tissues, we find Max inactivation alone produces pituitary adenomas while Max loss cooperates with Rb1/Trp53 loss to accelerate medullary thyroid C-cell and pituitary adenoma development. In the thyroid tumor cell lines, MAX loss triggers a striking shift in genomic occupancy by other members of the MYC network (MNT, MLX, MondoA) supporting metabolism, survival and proliferation of neoplastic neuroendocrine cells. Our work reveals MAX as a broad suppressor of neuroendocrine tumorigenesis through its ability to maintain a balance of genomic occupancies among the diverse transcription factors in the MYC network. TeaserMAX inactivation deregulates multiple transcription factors to induce neuroendocrine cancers

cancer biology↗

bioRxiv2022

Single-Cell Transcriptomic Analyses of Tumor Ecosystems and Spatial Architectures in Human Small Cell Lung Cancers

Small cell lung cancer (SCLC) is a highly heterogenous disease characterized by aggressive phenotypes and poor prognosis. In order to dissect the cellular components and their spatial distribution in SCLC ecosystems, here we performed single-cell RNA sequencing and spatial transcriptomics analyses of 12 resected human primary SCLCs. Our analysis revealed extensive heterogeneity of both tumor and non-tumor cells, and a predominant immunosuppressive microenvironment. Importantly, multiple hybrid tumor cell states were unmasked, including hybrid SCLC and lung adenocarcinoma cells as well as hybrid tumor and immune cells, indicating high phenotypic plasticity of tumor cells. Moreover, we revealed the cellular origin and evolution of these hybrid tumor cells, and critical roles of tumor-stromal cellular crosstalk in driving the development of hybrid cells. In conclusion, this study deepens our understanding of human SCLC ecosystems and provides rationales to target the hybrid tumor cells and immunosuppressive microenvironment for SCLC therapies.

cancer biology↗