Wilms’ tumor gene 1 expression is
upregulated during embryogenesis but is maintained at lower levels in adult
tissues (Pritchard-Jones et al, 1990). But it are overexpressed in many human
malignancies such as embryonic tumors, and acute myeloid leukemia (AML),
chronic myeloid leukemia (CML), and various solid tumors, including lung,
pancreatic, thyroid, breast, testicular, and ovarian carcinomas and melanoma
(Inoue et al, 1994).
The WT1 gene was initially defined as a tumor
suppressor gene (33 – 38), but on the basis of the existing evidence we find that
the WT1 gene induces the oncogenicity in normal cells (39). An example, leukemic
and solid cancer cell growth was inhibited by treatment with WT1-specific siRNA
(42) and WT1 antisense oligomers (40,41). On the other hand, in the transfected
cells involuntary expression of the WT1 gene promoted cell growth (43 – 45) by suppressing
apoptosis (47) and induced leukemia in WT1-transgenic mice (48).
High expression of the WT1 gene in solid tumors and leukemias
designated that the WT1 protein might be a promising tumor-associated antigen
(TAA). Gaiger et al. (53) stated that immunization with the murine MHC class
I-binding WT1 peptides p136 – 144, p235 – 243 and p117 – 139 persuaded
WT1-specific CTLs in mice and lysed WT1-over expressing tumor cells, although
no evidence of autoimmune toxicity was observed. Latter, Gao et al. (54) proved
that WT1 protein could well be an attractive tumor rejection antigen.
Several immune therapies exist to elicit against
tumor such as dendritic cell vaccine, immune check point inhibitors and chimeric
antigen receptor (CAR) therapy. But these therapies are not effective for
germline tumor cell therapy (Chaise et al, 2008).
Gene therapy is a new generation of treatment in which
genes are uses to treat cancer or any other disease. Researchers have been
developing different types of gene therapy to treat cancer.
This therapy needs a vehicle for delivery. This delivery vehicle might be viral
Viral vectors, such as adeno associated viral
vectors, retroviral vectors, and lentiviral vectors, offer effective gene
transduction and expression. Though, they have several disadvantages, including
high immune rejection, conceivable tumorigenicity, uncertain insertional
mutagenesis, and limited constructive sizes for gene insertion. These
disadvantages have prevented translation into clinical practice. On the
other hand, non viral vectors such as nanoparticles made by polymer, liposome,
lipid are used for efficient gene delivery. The nano based gene delivery has
some advantages including easy to synthesis, no risk of immune rejection, conceivable
tumorigenicity, and uncertain insertional mutagenesis. However, they have
several disadvantages, including toxicity and biocompatibility. To resolve this
problem scientist had used water-oil emulsion as a delivery vehicle. The water-oil
emulsion is a well-known adjuvant used for a centuries. Water-oil emulsion
protects the encapsulated DNA molecule from DNase digestion and it is fully biocompatible.
The emulsion is radially up taken by phagocytes which make the emulsion as a
potent delivery vehicle. In this work we used water-castor oil- water emulsion
to deliver mouse WT1 (mWT1) gene to the primary immunocytes. This bi-layerd
emulsion molecule can efficiently induces immunocytes and maintain a balances
between pro-inflammatory and anti-inflammatory cytokines which is essential to
maintain the immune therapy.