Efficient cotransduction of tumors by multiple herpes simplex vectors: Implications for tumor vaccine production

Abstract

Many gene therapy strategies would be enhanced by efficient transfer of multiple genes into the same cell. Herpes simplex viral amplicon (HSV) vectors are good vehicles for gene transfer because they accommodate large pieces of foreign DNA and transfer genes rapidly and efficiently. The current studies examine whether efficient cotransduction of tumor cells can be accomplished using multiple HSV vectors in a manner useful for clinical gene therapy. Interleukin-12 (IL-12) exists as a heterodimer, with components (m35 and m40) coded for by genes on two separate chromosomes. We constructed HSV vectors carrying either IL12m35 (HSVm35) or IL12m40 (HSVm40) or both genes (HSVm75) separated by an internal ribosome entry site to assess whether gene transfer using a single HSV vector constructed to carry multiple genes has any advantage over gene transfer using multiple vectors that are each carrying single genes. Because IL-12 and IL-2 have been found to have synergistic antitumoral activity, we further analyzed the biologic activity of tumor cells cotransduced by separate HSV vectors carrying genes coding for these two cytokines. The results demonstrate that multiple genes can be inserted into the same cell efficiently using multiple HSV vectors, and that these vectors allow rapid production of tumor vaccines expressing multiple cytokine genes. Thus, gene transfer using HSV may not be limited by the size of the DNA that each vector can accommodate. Immunizations with tumors cotransduced with HSVm35 and HSVm40 were equally effective in eliciting a cytolytic T-lymphocyte response and in protecting against tumor growth in vivo as immunization with tumors treated with HSVm75. Immunization with tumors cotransduced with HSVm75 and HSVil2 was superior to immunization with tumors transduced with either alone. The combination of IL-2-and IL-12-secreting tumor cells may be used as an effective immunization strategy against solid tumors. Cancer Gene Therapy (2000) 7, 581-588

Neoadjuvant Interleukin-12 Immunogene Therapy Protects Against Cancer Recurrence After Liver Resection in an Animal Model

“…14,16,19 -24 The cytokines most often used in such strategies include granulocyte-macrophage colony-stimulating factor, 10,18,23 interleukin 2 (IL-2), 14,16,19,20 and IL-12. 25,26 IL-12 is a heterodimeric protein that is a potent stimulator of natural killer cells and cytotoxic T lymphocytes. [27][28][29] Most cytokine gene transfer approaches are limited by inefficient gene delivery to the tumor.…”

“…The HSV vectors used in these experiments are replication-incompetent; the constructs have been previously characterized and described. 10,25 …”

HSV as a vector in vaccine development and gene therapy

“…[15][16][17][18][19] These include (1) delivery and expression of human genes to the nervous system cells, 20,21 (2) selective destruction of cancer cells, 22,23 (3) prophylaxis and immunotherapy against tumors 24,25 and (4) prophylaxis against infections with HSV and other infectious diseases. 26,27 In the viral genome there are approximately 80 gene products that can be classified as immediate early (IE or α), early (E or β) and late (L or γ) depending on their kinetics of expression during replication.…”

“…176,177 HSV amplicon vectors have also been evaluated as cancer vaccines by expressing combinations of cytokines and immunomodulatory proteins for treatment of a variety of experimental tumors. 24,175,[178][179][180][181] A promising, new approach to cancer is the selective degradation of mRNA by RNA interference (RNAi) 182 or interference with microRNAs that support tumor growth. 183 HSV amplicon vectors expressing siRNAs have been used recently to mediate posttranscriptional silencing of EGFR, which is frequently activated in human…”

Stat1 Deficiency in the Host Enhances Interleukin-12–Mediated Tumor Regression

“…IL-12 has several distinctive functions, such as inducing Th1 response, enhancing the generation of allospecific CD8 T cells, augmenting the proliferation of activating T and natural killer (NK) cells, and inducing the production and stabilization of IFN-g (1). Both recombinant IL-12 protein therapy and IL-12 gene therapy induce a significant inhibitory effect on the primary tumors or metastatic tumors in various tumor models and human clinical trial (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). IL-12 gene therapy has resulted in less toxicity than recombinant IL-12 protein therapy as tested in the RENCA tumor model (15).…”