Ninety percent of all cancers are solid tumours. Genetic researchers have discovered that “gene therapy represents a potential new modality to [tumour] treatment”. Currently, the most efficient approach to treatment has been viral vector based gene therapy systems. Due to certain deficiencies in viral vector systems cancer gene therapy has not reached its full potential. Restricting factors include: the requirement of intratumoural injection, which is impractical as many tumours are inaccessible or spread; cell heterogeneity vectors cannot efficiently kill every cancer cell; hypoxia reduces the functioning of vectors.
Hence, an alternate method of therapy has been investigated implementing the notion of a ‘Trojan horse’ vector. Obligate anaerobic bacteria “selectively colonise and regerminate in solid tumour when delivered systemically”. The clostridial spores of the bacteria possess additional tumour-killing capabilities and were easy to produce, stabilise and store. The combination of these spores with chemotherapy significantly produced a better result — ‘curing’ a high percentage of solid tumours in animals.
However, additional requirements need to be satisfied before the ‘Trojan horses’ can be implemented in clinical environments. These goals are to be achieved through developing technologies.
References: http://www.gvt-journal.com/content/6/1/8
Original journal: Clostridial spores as live 'Trojan horse' vectors for cancer gene therapy: comparison with viral delivery systems.
http://www.gvt-journal.com/content/6/1/8
