DNA, but not protein vaccine based on mutated BORIS antigen significantly inhibits tumor growth and prolongs the survival of mice

Abstract

The ideal immunological target for cancer vaccine development would meet the criteria of tumor specificity, immunogenicity and vital dependency of the tumor on the functional activities of the antigenic target so as to avoid antigenic loss by mutation. Given that at face value the brother of regulator of imprinted sites (BORIS) transcription factor meets these criteria, we have developed a mutant variant of this molecule (mBORIS) that lacks tumorigenic ability, while retaining immunogenic epitopes that elicits responses against histologically irrelevant tumor cells. Here we compared vaccine strategies employing as an immunogen either mBORIS recombinant protein formulated in a strong Th1-type adjuvant, QuilA or DNA encoding this immunogen along with plasmids expressing interleukin (IL)12/IL18 molecular adjuvants. In both groups of vaccinated mice induction of tumor-specific immunity (antibody response, T-cell proliferation, cytokine production, T-cell cytotoxicity) as well as ability to inhibit growth of the aggressive breast cancer cell line and to prolong survival of vaccinated animals have been tested. We determined that DNA, but not recombinant protein vaccine, induced potent Th1-like T-cell recall responses that significantly inhibited tumor growth and prolongs the survival of vaccinated mice. These studies demonstrate that DNA immunization is superior to recombinant protein strategy and provide a clear guidance for clinical development of a cancer vaccine targeting what appears to be a universal tumor antigen.

DNA prime–protein boost increased the titer, avidity and persistence of anti-Aβ antibodies in wild-type mice

“…One reason for these results is the low transfection efficacy of naked DNA 44,45. It is likely that a selection of an optimal DNA delivery system, such as a gene gun or electroporation, along with utilization of molecular adjuvants, could significantly enhance the efficiency of DNA vaccines 62–67. Additional augmentation of immune responses may be achieved by developing more effective immunization protocols.…”

Primary 4T1 tumor resection provides critical “window of opportunity” for immunotherapy

“…Miller (WSU, School of Medicine, Detroit, MI) and were cultured as previously described [27]. Freshly prepared, 15×10 3 tumor cells in mid-log growth phase were injected into the mammary fat pads as described in [28,29]. Tumor growth was monitored daily starting at day when tumors became palpable (usually at days 5–7 after injection of 4T1 cells).…”

Cancer-testis antigen, BORIS based vaccine delivered by dendritic cells is extremely effective against a very aggressive and highly metastatic mouse mammary carcinoma

“…Mice were sacrificed one week after the last immunization for the in vitro analyses. For the therapeutic studies, unmodified 4T1 mammary carcinoma cells were freshly prepared and 7×10 3 tumor cells were injected at day 0 into the mammary fat pads as described [24,26] followed by weekly immunizations with DC/mBORIS or DC/gp120. Tumor growth was monitored daily starting at day 12 when tumors became palpable as previously described [24,26].…”

“…For the therapeutic studies, unmodified 4T1 mammary carcinoma cells were freshly prepared and 7×10 3 tumor cells were injected at day 0 into the mammary fat pads as described [24,26] followed by weekly immunizations with DC/mBORIS or DC/gp120. Tumor growth was monitored daily starting at day 12 when tumors became palpable as previously described [24,26]. Tumor volumes were determined by two-dimensional measurement and calculation using the formula ( a × b 2 )/2, where a represents the largest diameter and b the smallest diameter of the tumor.…”

“…This unique epigenetically acting, tumor-promoting, transcription factor expressed in testis, also regulates the expression of other oncogenic molecules including MAGE-A1, NY-ESO-1, and SPANX [18,19,20,21,22]. Based on these observations and an important role for BORIS in oncogenic transformation [23], we tested a zinc finger deleted (modified) BORIS (mBORIS) in preventive studies and showed that delivery of this antigen by adenoviral [24] or DNA plasmid vectors [25,26] generated protective anti-tumor cellular immune responses, inhibited 4T1 mouse mammary tumor growth, and prolonged survival of vaccinated mice subjected to tumor challenge.…”