It's beautifully done, tells a whole proof of principle story, perfect for your journal club too!

download it here at Nature Biomedical Engineering:
rdcu.be/eH4le

BUT now, a million years later, my lab is revisiting all this stuff, saRNA vaccines, bacterial delivery systems, oncolytic therapies, with a modern updated touch.

READ this very cool paper by SINGER et al, one of my favourites for 2025 for sure!

We packaged all this up in a patent, but never published...because in the meantime, all that work on ribavirin resistance & polymerase fidelity side project took my career in a different direction!

to see the Salmonella stuff...it's buried in our patent:

patents.google.com/patent/US739...

The enzyme produced by asd gene (Aspartate-semialdehyde dehydrogenase) is essential for diaminopimelic acid (DAP) synthesis.

The Asd gene knockout meant that we could produce Salmonella in broth supplemented DAP, while in the host cell, the bacteria falls apart - missing its peptidoglycan wall.

This was my dream as a postdoc! Spent years knocking out S typhimurium of sifA, orgA and Asd genes. My PhD developed the 1st polio saRNA vectors, and in Andino lab, I engineered S.typhimurium to deliver like Trojan horse to gut macrophages, delivering Yellow Fever & polio RNA in vitro and in vivo.

To restrict the spread of the oncolytic virus, they swapped one protease cleavage sites with that of Tobacco Etch virus, so only cells expressing TEVpro from the Salmonella can produce full virus. Cool safety switch!

Impressively, these oncolytic viruses launched from T7 RNA promoter in Salmonella expressing T7 polymerase, significantly reduce tumours at the injection site and at other sites, fully protecting mice against the disease.

They use this bacteria to invade a cell and deliver an oncolytic Senecavirus RNA, which replicates, and spreads to neighbouring tumours.

They added hylE and bacteriophage E lysis genes to break the Salmonella apart to further deliver its contents into the cytoplasm. In our approach, we knocked out the Asd gene that is needed to maintain bacerial wall integrity to have the same effect.

When Salmonella infect cells, they hide themselves in a Salmonella Containing Vacuole, the sifA gene helps maintain this vacuole, both these authors and we knocked this gene out so that the Salmonella would fall into the cytoplasm for RNA delivery.

Here, they show its value as a therapeutic in vivo.

The authors use Salmonella typhimurium to encode T7 polymerase, lysis proteins and an expression cassette to launch RNA virus replicons or full viruses. The goal : to deliver these viruses to tumor cells and lyse the tumors.