Misra, B. | Search bioRxiv

bioRxiv2025

Development of a Stable Lyophilized Formulation of a Quadrivalent Frame-Shift Peptide Vaccine for Cancer Prevention in Lynch Syndrome

A stable lyophilized formulation for a cancer vaccine containing quadrivalent frameshift neo antigen peptides TAFB(-1), AIM2(-1), HT001(-1) and TGFBR2(-1), was obtained through an iterative screening process. To develop a lyophilized formulation, the screening included evaluation of pH, stabilizers, bulking agents, and surfactants. The screening resulted in a scalable formulation and lyophilization process that co-formulated four peptides with 100 {micro}g/ml each peptide in10 mM Histidine at pH 5.5, 260 mM trehalose, and 0.02% polysorbate 20 as a clinical formulation. Based on peptide content and peptide purity from a three-month stability study, the lyophilized formulation is estimated to be stable at ambient temperatures for 18 months.

pharmacology and toxicology↗

bioRxiv2024

Intratumoral administration of mRNA-1273 vaccine delays melanoma growth in mice

BackgroundImmunotherapies are advantageous for treating cancers; however, their efficacy is limited in unresponsive hosts with "cold" tumor microenvironments. This limitation primarily stems from the lack of infiltrating CD8+ T cells, which are major effectors of the anti-cancer immune response. Here, we demonstrate the effects of intratumoral (IT) injections of the COVID-19 mRNA vaccine on the impairment of tumor growth in mice. MethodsEstablished B16F10 subcutaneous tumor models in wild type mice were used to evaluate the tumor response from IT administration of mRNA-1273. We compared treatment outcomes, immune composition, and transcriptomic effects from mRNA-1273 using survival studies, intravital imaging, flow cytometry, single-cell RNA sequencing, and abscopal studies. The ability of mRNA-1273 to enhance immune checkpoint therapy response was also evaluated. ResultsTumor growth and survival studies following a single IT injection of the COVID-19 mRNA-1273 vaccine showed significant tumor suppression and prolonged survival in tumor-bearing mice. mRNA-1273 treatment resulted in a significant increase in CD8+ T cell infiltration into the tumor microenvironment, as observed using intravital imaging and flow cytometry. Further tumor growth suppression was achieved using additional mRNA-1273 treatments. Combination administration of mRNA-1273 with immune checkpoint therapies demonstrated enhanced effects, further delaying tumor growth and improving the survival time of tumor-bearing mice. ConclusionIT injection of mRNA-1273 significantly reduced tumor growth and enhanced CD8+ T cells in the tumor microenvironment. Tumor suppression was further enhanced following multiple injections of mRNA-1273 or when combined with immune checkpoint therapies. This study demonstrates that mRNA vaccines may be used as adjuvants for immunotherapies. What is already known on this topicO_LIMost cancer patients develop adequate antibody response to vaccination with mRNA-1273 and produce spike-specific T cell responses. However, it is unclear if the mRNA-1273 vaccine can be used to elicit anti-tumor T cell responses. C_LI What this study addsO_LIIntratumoral injection of mRNA-1273 significantly delayed melanoma growth. C_LIO_LITreatment with mRNA-1273 significantly increased CD8+ T cell infiltration into the tumor microenvironment. C_LIO_LIEnhanced effects of combination mRNA-1273 and immune checkpoint therapy in anti-tumor immunity. C_LI How this study might affect research, practice, or policyO_LImRNA vaccine may be an effective adjuvant with immune checkpoint therapy. C_LI

immunology↗

bioRxiv2021

Conformational Change of Syntaxin-3b in Regulating SNARE Complex Assembly in the Ribbon Synapses

Neurotransmitter release of synaptic vesicles relies on the assembly of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex, consisting of syntaxin and SNAP-25 on the plasma membrane and synaptobrevin on the synaptic vesicle. The formation of the SNARE complex progressively zippers towards the membranes, which drives membrane fusion between the plasma membrane and the synaptic vesicle. However, the underlying molecular mechanism of SNARE complex regulation is unclear. In this study, we investigate the syntaxin-3b isoform found in the retinal ribbon synapses using single-molecule fluorescence resonance energy transfer (smFRET) to monitor the conformational changes of syntaxin-3b that modulate the SNARE complex formation. We found that syntaxin-3b is predominantly in a self-inhibiting closed conformation, inefficiently forming the ternary SNARE complex. Conversely, a phosphomimetic mutation (T14E) at the N-terminal region of syntaxin-3b promoted the open conformation, similar to the constitutively open form of syntaxin LE mutant. When syntaxin-3b is bound to Munc18-1, SNARE complex formation is almost completely blocked. Surprisingly, the T14E mutation of syntaxin-3b partially abolishes Munc18-1 regulation, acting as a conformational switch to trigger SNARE complex assembly. Thus, we suggest a model where the conformational change of syntaxin-3b induced by phosphorylation initiates the release of neurotransmitters in the ribbon synapses.

neuroscience↗