Biology subjects

Vincent, R. L.

Publications and source records attributed to Vincent, R. L..

5 recordsLinked to original sources

bioRxiv2026

NanoPro - a Framework for Probiotically-Guided Nanovector Therapy

The 'antigen problem', i.e. the disconnect between the broad spectrum of therapeutic modes enabled by the range of viral and synthetic nanoparticles for which workable receptor-targeting architectures exist and the relative dearth of addressable target receptors on most tumors, is a long-standing challenge in targeted tumor nanotherapy. Here we provide in vitro-proof-of-principle for NanoPro, a platform for guiding nanoscale therapeutics to otherwise antigenically indistinct tumors via probiotically-released tumor cell-binding tags, ProTags. These consist of an orthogonal antigen (GFP or ALFA) fused to the heparin-binding domain of placenta growth factor-2 and serve as attachment receptors for ProTag-targeted nanovectors. ProTag release from Escherichia coli Nissle 1917 was facilitated by deletion of the membrane-tethering lpp gene, which increased ProTag supernatant concentrations 16.5-fold compared to the parental strain without impacting viability. HBD-dependent decoration with ProTag in bacterial supernatant followed by treatment with receptor-targeted aGFP- or aALFA-lentiviral vectors resulted in majority transduction of MC-38 and MDA-MB-468 tumor cell lines with antigen specificities of 96.5% and 98.5%, respectively, depending on the choice of nanobody. This ProTag-mediated interaction was notably robust, with selective transduction still observed at 625-fold supernatant dilution, warranting further exploration of the utility of the NanoPro system for tumor-restricted delivery of nanotherapeutics.

synthetic biology↗

bioRxiv2024

Tumor-specific antibodies elicited by engineered bacteria promote bladder cancer immunotherapy

The intratumoral microbiome has recently emerged as a new hallmark of cancer, with implications for response or resistance to therapy. While bacteria can either promote or inhibit cancer growth, intratumoral bacteria can also be engineered using synthetic biology to remodel the tumor microenvironment. Here, we engineered the probiotic bacterium E. coli Nissle 1917 (EcN) to express the human chemokine CXCL13, a critical component of germinal center (GC) formation. The GC reaction is a fundamental aspect of adaptive immunity by which antibody affinity develops in secondary lymphoid organs for defense against pathogens. Using orthotopic models of bladder cancer, engineered CXCL13-expressing EcN colonized bladder tumors and elicited GC responses in bladder tumor-draining lymph nodes after intravesical delivery. Furthermore, when combined with PD-1 blockade, engineered EcN amplified the antitumor antibody response and promoted long-term survival and protective immunity upon tumor rechallenge. Thus, we demonstrate that synthetically engineered CXCL13-expressing EcN can enhance the efficacy of PD-1 checkpoint blockade immunotherapy by amplifying tumor-specific humoral immunity.

immunology↗

bioRxiv2023

Probiotic neoantigen delivery vectors for precision cancer immunotherapy

Microbial systems have been synthetically engineered to deploy therapeutic payloads in vivo1-4. With emerging evidence that bacteria naturally home to tumors5-7 and modulate anti-tumor immunity8,9, one promising application is the development of bacterial vectors as precision cancer vaccines10-12. In this study, we engineered probiotic E. coli Nissle 1917 (EcN) as an anti-tumor vaccination platform optimized for enhanced production and cytosolic delivery of neoepitope-containing peptide arrays, with increased susceptibility to blood clearance and phagocytosis. These features enhance both safety and immunogenicity, achieving a system which drives potent and specific T cell-mediated anti-cancer immunity that effectively controls or eliminates tumor growth and extends survival in advanced murine primary and metastatic solid tumors. We demonstrate that the elicited anti-tumor immune response involves extensive priming and activation of neoantigen-specific CD4+ and CD8+ T cells, broader activation of both T and NK cells, and a reduction of tumor-infiltrating immunosuppressive myeloid and regulatory T and B cell populations. Taken together, this work leverages the advantages of living medicines to deliver arrays of tumor-specific neoantigen-derived epitopes within the optimal context to induce specific, effective, and durable systemic anti-tumor immunity.

synthetic biology↗

bioRxiv2022

Engineered bacteria recruit and orchestrate anti-tumor immunity

Tumors employ multiple mechanisms to actively exclude or suppress adaptive immune cells involved in anti-tumor immunity. Strategies focused on overcoming these immunosuppressive or exclusion signals - through localized delivery of chemokines that directly recruit immune cells into the tumor microenvironment - remain limited due to an inability to target therapeutics specifically to the tumor. Synthetic biology enables engineering of cells and microbes for tumor localized delivery, offering therapeutic candidates previously unavailable using conventional systemic administration techniques. Here, we engineer bacteria to produce and intratumorally release chemokines to attract adaptive immune cells into the tumor environment. Intravenous or intratumoral delivery of bacteria expressing an activating mutant of the human chemokine CXCL16 (hCXCL16K42A) leads to the recruitment of activated T cells within tumors and offers therapeutic benefit in multiple mouse tumor models. Furthermore, we rationally target an additional step in the immune activation cascade - specifically, the presentation of tumor-derived antigens by dendritic cells - using a second engineered bacterial strain expressing CCL20. This combined targeting approach led to the recruitment of type 1 conventional dendritic cells and effectively synergized with hCXCL16K42A-induced T cell recruitment to provide additional therapeutic benefit. In summary, we engineer bacteria to cooperatively recruit and activate both innate and adaptive anti-tumor immune responses, offering a new cancer immunotherapy strategy.

cancer biology↗

bioRxiv2021

Probiotic-guided CAR-T cells for universal solid tumor targeting

Synthetic biology enables the engineering of interactions between living medicines to overcome the specific limitations of any singular therapy. One major challenge of tumor-antigen targeting therapies like chimeric antigen receptor (CAR)-T cells is the identification of targetable antigens that are specifically and uniformly expressed on heterogenous solid tumors. In contrast, certain species of bacteria selectively colonize immune-privileged tumor cores and can be readily engineered as antigen-independent platforms for therapeutic delivery. Bridging these approaches, we develop a platform of probiotic-guided CAR-T cells (ProCARs), in which T cells are engineered to sense synthetic antigens (SA) that are produced and released by tumor-colonizing probiotic bacteria. We demonstrate increased CAR-T cell activation and tumor-cell lysis when SAs anchor to components of the extracellular matrix. Moreover, we show that ProCARs are intratumorally activated by probiotically-delivered SAs, receive further stimulation from bacterial TLR agonists, and are safe and effective in multiple xenograft models. This approach repurposes tumor-colonizing bacteria as beacons that guide the activity of engineered T cells, and in turn builds the foundation for communities of living medicines.

bioengineering↗