A novel placental like alkaline phosphate promoter driven transcriptional silencing combined with single chain variable fragment antibody based virosomal delivery for neoplastic cell targeting

作者：Khan Imran; Zakaria Mohammad Khalid; Kumar Mukesh; Mani Prashant; Chattopadhyay Parthaprasad; Sarkar Debi P; Sinha Subrata

来源：Journal of Translational Medicine, 2015, 13(1): 254.

DOI：10.1186/s12967-015-0602-1

• Placental like alkaline phosphate
• Promoter
• HPV-16
• Transcriptional gene silencing
• Recombinant antibody
• scFv
• Sendai virosome
• Gene therapy
• Germ cell alkaline phosphate (GCAP)

Background: Placental like alkaline phosphate (PLAP), an oncofetal antigen, is highly expressed in germ cell, cervical, ovarian and several other tumour types but minimally in normal tissues. The expression of a PLAP promoter based transcriptional unit following antigen mediated cell specific delivery is a possible approach for tumour targeting.
Methods: PLAP promoter alone or in combination with NF kappa B DNA response elements was used for expressing shRNA targeting the long control region (LCR) of human papillomavirus (HPV)-16 oncogenes E6 and E7 via transcriptional gene silencing in PLAP expressing cervical cancer cell lines, SiHa and CaSki. This was packaged in a Sendai virus envelope incorporating a single chain variable fragment antibody (scFv) for antibody mediated targeting. Specificity and efficacy of the shRNA was assessed by studying the heterochromatization, down regulation of the HPV-16 E6/E7 genes and subsequent effects on their targets and cell growth properties.
Results: Reduction of HPV-16 E6 and E7 expression by TGS led to the activation of the previously suppressed target genes of p53 (PUMA and NOXA) and Rb (cyclins A2 and E). Cell death was seen only in PLAP expressing HPV-16 infected SiHa and CaSki cells but not in the HPV-18 integrated HeLa and non-PLAP CHO cells. There was reduction in the enhancer associated transcripts of the long control region (LCR) of HPV-16 E6/E7 genes. Also, an increase in the enrichment of dimethylated histone three lysine nine (H3K9Me2) and trimethylated histone three lysine twenty-seven (H3K27Me3) was observed by ChIP assay, which decreased upon trichostatin A treatment, indicating a possible mechanism for the heterochromatization of the target LCR region.
Conclusion: A combination of novel PLAP promoter and antibody based specificities has the potential for being developed as a possible therapeutic strategy for PLAP positive neoplasia.

• 出版日期2015-8-5
• 单位河北医科大学