Targeted inactivation of Salmonella Agona metabolic genes by group II introns and in vivo assessment of pathogenicity and anti-tumour activity in mouse model

Chin Piaw Gwee, Chai Hoon Khoo, Swee Keong Yeap, Geok Chin Tan, Yoke Kqueen Cheah

Research output: Contribution to journalArticle

Abstract

The fight against cancer has been a never-ending battle. Limitations of conventional therapies include lack of selectivity, poor penetration and highly toxic to the host. Using genetically modified bacteria as a tumour therapy agent has gained the interest of scientist from the past few decades. Low virulence and highly tolerability of Salmonella spp. in animals and humans make it as the most studied pathogen with regards to anti-tumour therapy. The present study aims to construct a genetically modified S. Agona auxotroph as an anti-tumour agent. LeuB and ArgD metabolic genes in ∆SopB∆SopD double knockout S. Agona were successfully knocked out using a Targetron gene knockout system. The knockout was confirmed by colony PCR and the strains were characterized in vitro and in vivo. The knockout of metabolic genes causes significant growth defect in M9 minimal media. Quadruple knockout ∆SopB∆SopD∆LeuB∆ArgD (BDLA) exhibited lowest virulence among all of the strains in all parameters including bacterial load, immunity profile and histopathology studies. In vivo anti-tumour study on colorectal tumour bearing-BALB/c mice revealed that all strains of S. Agona were able to suppress the growth of the large solid tumour as compared with negative control and ∆LeuB∆ArgD (LA) and BDLA auxotroph showed better efficacy. Interestingly, higher level of tumour growth suppression was noticed in large tumour. However, multiple administration of bacteria dosage did not increase the tumour suppression efficacy. In this study, the virulence of BDLA knockout strain was slightly reduced and tumour growth suppression efficacy was successfully enhanced, which provide a valuable starting point for the development of S. Agona as anti-tumour agent.

Original languageEnglish
Article numbere5989
JournalPeerJ
Volume2019
Issue number1
DOIs
Publication statusPublished - 1 Jan 2019

Fingerprint

Salmonella Agona
Salmonella
Introns
Virulence
introns
Tumors
inactivation
pathogenicity
Genes
animal models
neoplasms
Neoplasms
genes
auxotrophs
Gene Knockout Techniques
virulence
Growth
therapeutics
Bacteria
Bearings (structural)

Keywords

  • Anti-tumour therapy
  • ArgD gene
  • Attenuated Salmonella Agona
  • Colorectal cancer
  • Group II intron
  • LeuB gene

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

Targeted inactivation of Salmonella Agona metabolic genes by group II introns and in vivo assessment of pathogenicity and anti-tumour activity in mouse model. / Gwee, Chin Piaw; Khoo, Chai Hoon; Yeap, Swee Keong; Tan, Geok Chin; Cheah, Yoke Kqueen.

In: PeerJ, Vol. 2019, No. 1, e5989, 01.01.2019.

Research output: Contribution to journalArticle

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