162P - Dual punch tumour-specific transcriptional gene silencing inducing therapeutic approach based on novel tumour-specific promoter and recombinant Sen...

Date 28 September 2014
Event ESMO 2014
Session Poster Display session
Topics Basic Science
Cancer Immunology and Immunotherapy
Presenter Imran Khan
Citation Annals of Oncology (2014) 25 (suppl_4): iv53-iv57. 10.1093/annonc/mdu325
Authors I. Khan, K. Zakariya, P. Mani, P. Chattopadhyay, D.P. Sarkar, S. Sinha
  • Biochemistry, All India Institute of Medical Sciences, 110029 - New Delhi/IN

Abstract

Aim

Lack of selectivity and cell-specific delivery to malignant cells are the major obstacles for the success of cancer therapies. Treatment with current conventional modalities has reached an impasse suggesting the need for their refinement. This study therefore aims at the development of tumour-specific transcriptional gene silencing (TGS) inducing therapeutic modalities.

Methods

Placental-like alkaline phosphatase (PLAP) is ectopically expressed in a wide range of tumours and consequently its promoter is active only in such neoplastically transformed cells with little or no activity in normal cells. We used novel tumour PLAP promoter either alone or in combination with a tumour-specific enhancer system for the induction of TGS in various HPV-16-integrated cellular systems. Promoter-mediated expression of shRNA targeting the common long control region of E6/E7 imparted one level of specificity which was honed further by utilising PLAP scFv based engineered Sendai virosomes for packaging and delivery of these therapeutic constructs.

Results

Regression in expression of E6& E7 ameliorated p53 and its target genes only in SiHa and CaSki but not in HeLa and CHO cells demonstrating the specificity of both shRNA expression as well as delivery of the cargo by recombinant virosomal vehicular traffic. TGS was induced in various in vitro models of HPV-16 by heterochromatization of the targeted region but no DNA methylation was noted. A fall in the level of an enhancer-associated transcript was observed after the shRNA treatment.

Conclusions

A combination of promoter and antibody based specificities has the potential for being developed as a possible therapeutic strategy for neoplasia.

Disclosure

All authors have declared no conflicts of interest.