Introduction

We love iGem so much because it gives us a sense of inheritance. Here, we can see many summaries, methods and innovative ideas from our predecessors. These knowledge help us design our projects in the early stage, and inspire us to solve problems when we encounter difficulties. This is a kind of mutual help across time and countries, which is also what we hope to see in scientific research! Now we are very happy to leave our experience behind, hoping to help the future teams!

Part

Fig 1. Schematic structure model of the influenza A virion

By elucidating the mechanisms underlying influenza virus infection and exploiting the specific interactions between viral surface proteins and cellular receptors, our research aims to contribute to the development of targeted oncolytic virotherapy, providing novel and effective treatment. One of the most important efforts is to modify the proteins on the surface of the influenza virus to improve its targeting of tumor cells.

Fig 2. Swapped HA and NApackaging signals

A notable feature of influenza virus is the disproportionate abundance of the hemagglutinin (HA) protein relative to neuraminidase (NA) protein on its surface. To further enhance the selectivity of influenza virus towards tumor cells, we propose a novel approach. Specifically, we plan to swap the packaging signals of HA and NA, leading to the packaging of a higher quantity of NA on the viral surface. The rationale behind this strategy lies in the fact that tumor cells often overexpress TfR1, making them more susceptible to viral entry and internalization. By increasing the presence of NA on the viral envelope, we anticipate that the modified influenza viruses will exhibit enhanced affinity towards TfR1 on tumor cells, thereby increasing their selectivity and infectivity towards cancerous tissues.

We created the basic part BBa_K4638010 and BBa_K4638011, which are the packaging signals of HA. As well as BBa_K4638012 and BBa_K4638013 are the packaging signals of NA.

We created the composite part BBa_K4638020 and BBa_K4638021 . BBa_K4638020 is the synonymous mutated Neuraminidase (NA) of WSN in the signaling sequence of Hemagglutinin (HA), while BBa_K4638021 is the synonymous mutated Hemagglutinin (HA) of WSN in the signaling sequence of Neuraminidase (NA).

Fig 3. Insertions and deletions in the stalk region of the NA protein

Moreover, we extend the stalk domain of NA. The NA protein comprises a globular head domain and a stalk domain. Previous studies have shown that elongating the stalk domain of NA can enhance its immunogenicity.

Our team created and documented the created parts onto the Parts Registry. These parts contribute together to the increased exposure of NA, facilitating its binding to ligands.

We created the composite part BBa_K4638006 and BBa_K4638007. BBa_K4638006 is the NA protein that its stalk is lengthened by 14 amino acids, while BBa_K4638007 is lengthened by 28 amino acids.

These modifications can enhance the targeting of the flu virus to the tumor, which is hoped to provide inspiration for future teams.

Booklet

In the booklet Handbook of Microbial Mediated Tumor Therapy in Synthetic Biology jointly written and published by six schools, our team completed a review of oncolytic viruses (P3-13), ethical considerations on the use of viruses for tumor therapy (P46-49) and human practices (P50-53). In the review section, we focus on the relevant mechanisms of tumor selectivity of oncolytic viruses, the currently developed technology of modification of oncolytic viruses, and related clinical applications. In the ethical thinking section, we explore the feasibility and advantages of using oncolytic viruses for tumor therapy, bringing our PekingHSC insights to the field. We hope that the work we have done will be helpful to the teams that participate in the competition and choose the direction related to oncolytic viruses, and help to understand oncolytic viruses and provide new ideas for transformation.

click to download handbook.pdf

Reference

[1]Si, L., Shen, Q., Li, J. et al. Generation of a live attenuated influenza A vaccine by proteolysis targeting. Nat Biotechnol 40, 1370–1377 (2022). https://doi.org/10.1038/s41587-022-01381-4

[2]Zheng, A., Sun, W., Xiong, X., Freyn, A. W., Peukes, J., Strohmeier, S., Nachbagauer, R., Briggs, J. A. G., Krammer, F., & Palese, P. (2020). Enhancing Neuraminidase Immunogenicity of Influenza A Viruses by Rewiring RNA Packaging Signals. Journal of virology, 94(16), e00742-20.https://doi.org/10.1128/JVI.00742-20

[3]Broecker, F., Zheng, A., Suntronwong, N., Sun, W., Bailey, M. J., Krammer, F., & Palese, P. (2019). Extending the Stalk Enhances Immunogenicity of the Influenza Virus Neuraminidase. Journal of virology, 93(18), e00840-19.https://doi.org/10.1128/JVI.00840-19